Wet Cell vs. AGM Batteries & Wiring Tips for Installation on an RV or Boat!

There is a world of difference between wet cell batteries (also called flooded batteries) and AGM batteries for use in an RV or marine battery bank, because AGM batteries are totally sealed, maintenance free and keep the user from coming into contact with battery acid (electrolyte). In a nutshell, the advantages of AGM batteries over wet cell batteries are the following:

  • AGM batteries are maintenance free, which means:
    • They don’t need periodic equalizing to clean the internal plates and never need the electrolyte topped off with distilled water.
    • They do not release gasses during charging, so they don’t need special venting in the battery compartment.
    • Since gasses are not released, the terminals and battery cables do not corrode over time and don’t need to be cleaned.
  • AGM batteries discharge more slowly than wet cells, so an RV or boat can be stored for a few months without charging the batteries.
  • AGM batteries charge more quickly than flooded batteries because they can accept a higher current during the Bulk charging phase.
  • AGM batteries can be installed in any orientation, which is helpful if installation space is limited.
  • AGM batteries can’t spill battery acid if they are tipped over. This is especially important when a boat heels excessively or capsizes. (Not that you’d be too concerned about spilling electrolyte if your boat were upside down!)
RV battery upgrade from 6 volt wet cell batteries to AGM batteries



We used Trojan T-105 wet cell (flooded) batteries for nearly six years in our fifth wheel trailer, and they worked great. They were installed in our basement compartment, all lined up in a row. This was a custom installation that was done by H&K Camper Sales in Chanute, Kansas, when we purchased our trailer new from the NuWa factory in 2008.

Fifth wheel RV battery boxes in basement

Four 6 volt golf cart batteries installed in our fifth wheel basement

The original battery compartment was designed at the NuWa factory to hold two 12 volt Group 24 batteries. Group 24 batteries have the same footprint as 6 volt golf cart batteries but are about an inch shorter. We had 2″ angle iron bolted onto our fifth wheel frame so the four batteries could stand side by side in battery boxes.

Angle iron supports under an RV fifth wheel battery bank

2″ angle iron is bolted onto the fifth wheel frame
to support the batteries.

There were four venting flex hoses that ran from the battery boxes to four individual louvered vents on the front of the basement on either side of the hatch door.

RV 5th wheel basement with 6 volt battery boxes

Each battery box is vented to the outside with flex hose going to a louvered vent cover.

These batteries worked well, but because we put our RV in covered storage for 4 to 20 months at a time during the four years we cruised Mexico’s Pacific coast on our sailboat, we were not actively present to take care of the the battery charging and maintenance duties. Despite our best efforts to have someone do this while we were gone, when we moved off of our boat and back into our fifth wheel, we found our four Trojan wet cell batteries were completely dead and unrecoverable.

We replaced these batteries with four inexpensive 6 volt golf cart flooded batteries from Costco. These new batteries did not last. Within 18 months, the internal plates had sulfated badly, they took forever to charge, and they discharged extremely quickly.

6 volt wet cell batteries in fifth wheel RV basement

Upgrade time! We removed the old wet cell batteries and replaced them with AGMs.

In April, 2015, while staying in beautiful Sarasota, Florida, we replaced our wet cell batteries with four fabulous new Trojan Reliant T105-AGM batteries that Trojan had just begun manufacturing and selling. We replaced all the wiring as well.


One of the biggest problems with wet cell, or flooded, batteries is that the battery terminals and ring terminals on the battery cables get corroded easily due to the gassing that goes on when the batteries are being charged. When Mark removed the battery cables from our old batteries, he measured as much as 20 ohms of resistance from the end of each cable to its ring terminal.

Corrosion on battery cable

We measured 20 ohms of resistance between the end of the cable
and the end of the ring terminal.

Flooded batteries need to be held at 14.5 or more volts during the Absorption charging stage (depending on the battery), and at this voltage the electrolyte in the batteries begins to release gasses into the air. These gases are both explosive and corrosive, and venting them protects everything around them. However, inside the battery box these gases can corrode the battery terminals and wiring.

The best way to clean off the corrosion is with a solution of baking soda and distilled water. Put it in a disposable cup and then use a cheap paintbrush to paint it on and smooth it around the terminals and cable ends. Let it sit for a few minutes and then pour a little distilled water over it to rinse the baking soda and crud off. Dry it with paper towels.

Also, while driving down the road, the electrolyte can splash around inside the battery cells and drip out the vent holes. Dust can settle on the spilled electrolyte and can cause a minute trickle discharge across the top of the battery. So, it is important to wipe down the tops of the batteries regularly and keep them clean.

It’s a good idea to wear rubber gloves for all of this too!

6 volt wet cell RV house batteries

These batteries did not hold up well and corroded badly every few weeks.

Watch out for drops of liquid settling on your clothes when messing with the batteries. It’s nearly impossible to avoid, and Mark has holes in some of his jeans from drops of battery acid landing on his pants while he either checked the state of charge of the batteries with a hydrometer or poured distilled water into the battery terminals or cleaned the corrosion from the battery terminals and cable connections.

Battery hydrometer not used with AGM batteries

Now that we have nifty new AGM batteries, we no longer need the hydrometer!


We chose the new Trojan Reliant T105-AGM batteries to replace our old flooded batteries because these are a completely redesigned battery from one of the top battery manufacturers, Trojan Battery. Rather than being dual purpose batteries, like othe AGM batteries on the market, the new Trojan Reliant AGM batteries are single purpose deep cycle batteries.

Trojan Reliant AGM 6 volt RV batteries

Our new Trojan Reliant T105-AGM batteries ready to go.


Large RV and marine batteries can be used both to start big engines and to run household appliances. However, these functions are polar opposites of each other! A start battery gives a big but short blast of current to get an engine started and then does nothing. In contrast, a house battery provides a steady stream of current to power lights and household appliances for hours on end.

Most deep cycle AGM batteries on the market today are actually dual purpose start and deep cycle batteries, largely due to the history of how batteries have developed and what they have been used for. The new-to-market (in 2015) Trojan Reliant AGM batteries were engineered from the ground up to be strictly deep cycle batteries, and the design is not compromised with start battery characteristics.

Installing Trojan 6 volt Reliant AGM battery in RV fifth wheel

Mark installs the new batteries in the old plastic battery boxes.

12 volt batteries come in many sizes: Group 24, Group 27, Group 31, 4D, 8D and more. As the battery sizes increase, they provide more and more amp-hour capacity. 6 volt batteries come in various sizes too, and the golf cart size is one of several.

The Trojan Reliant T105-AGM 6 volt golf cart style batteries (68 lbs. each) are rated to have a capacity of 217 amp-hours when two of them are wired in series to create a 12 volt battery bank. In comparison, our sailboat came with three Mastervolt 12 volt 4D AGM batteries (93 lbs. each), and we added a fourth. These batteries were rated to have a capacity of 160 amp-hours each.

The advantage of using two 6 volt golf cart batteries instead of enormous 4D or 8D 12 volt batteries is that they are smaller, lighter and easier to carry around and to put in place during the installation and easier to remove in the event of a failure.


We wired our four new 6 volt batteries in series and in parallel. We wired two pairs of batteries in series to create two virtual 12 volt battery banks. Then we wired those two 12 volt banks in parallel with each other.

Four 6 volt batteries wired in series and in parallel

Four 6 volt batteries: two pairs wired in series to make virtual 12 volt batteries.
Those pairs are wired in parallel with each other (red / lavender circles explained below).

Trojan Battery recommended the following wire sizes for this battery configuration:

  • 4 gauge wire between the batteries that are wired in series
  • 2 gauge wire between the pairs of 12 volt battery banks wired in parallel

This is thicker wire than many RVers and sailors typically select for their battery banks.

Because we were wiring batteries that would be physically lined up in a row, we drew out a wiring diagram to be sure we got it right.

Four 6 volt batteries in a row wired in series and in parallel

Same wiring but with the batteries lined up in a row (red and lavender circles explained below).


Because AGM batteries have a lower internal resistance, they can accept a higher bulk charging current than wet cell batteries.

Trojan Reliant AGM batteries can accept a bulk charge current of 20% of their 20 hour amp-hour rating. For the T105-AGM batteries, the 20 hour amp-hour rating is 217 amps per pair of batteries wired in series. So the max current the batteries can accept is 20% of 217 amps, or 43 amps, per pair. The wiring for each charging system should be sized for a max current flow of 43 amps.

In contrast, Trojan’s wet cell batteries can accept only 10%-13% of their 20 hour amp-hour rating. For the T105 battery, the 20 hour amp-hour rating is 220 amps per pair of batteries wired in series. So the max current the batteries can accept is 13% of 220 amps, or 28 amps.

It is important when wiring both the battery charging systems and inverter systems into the battery bank (that is, the solar charge controller, the engine alternator on boats and motorhomes, the inverter/charger or the individual DC converter and inverter), to ensure that the wiring going to those devices is connected across the entire battery bank and not to just one 12 volt battery (or 6 volt pair) in the bank.

If the charging systems are connected to the battery terminals of just one 12 volt battery, whether it’s an individual Group 24 or 4D battery or is a pair of 6 volt golf cart batteries wired in series, then the batteries in the system will not charge equally. Likewise, if only one battery of the parallel bank is wired to the DC side of the inverter, the batteries will not discharge equally.

In the above drawings, the two optimal connection points for the charging and inverter systems are shown in red and in lavender. Either pair of terminals works equally well.

We found that with individual devices for our converter, our inverter and our solar charge controller, there were a lot of ring terminals getting piled up on two of the battery terminals. So we chose the inner pair of battery terminals for the inverter and the outer pair for the converter and solar charge controller.

Since we dry camp 100% of the time and rarely use our converter except when we have to pull out our generator after days of storms or to run our air conditioning, this division means that our primary charging system spans the batteries one way while the inverter driving the AC household systems that discharge the batteries span the batteries the other way.


We chose Ancor marine wire for our battery cables because it is very high quality cable. The individual strands of wire inside the casing are thin, which makes this cable very supple, despite being thick overall. It is easy to work with and to snake around tricky areas. The individual strands inside the cable are tinned as well.

This is expensive wire, but after all the wiring projects we have done on our RVs and on our sailboat, we felt it was well worth the extra cost.

We also used Ancor marine tin plated lugs made of high-grade copper with flared ends for our ring terminals (available here).

Ring terminal on battery cable

Mark slips a ring terminal onto the new battery cable.

It was critical to get a good solid connection between the ring terminals and the 2 gauge and 4 gauge wire we were using.

We don’t own a crimper of that size, but West Marine Stores often have a crimper for heavy gauge wire that customers can use, and we got an excellent crimp from a workbench mounted crimper.

Crimping ring terminal on battery cable

Crimping 2 and 4 gauge wire requires a large crimper.

With Mark hanging onto the ring terminal and me hanging onto the wire, we both pulled with all our might and we couldn’t pull the lug off the wire.

Good crimp on battery cable

A good, solid crimp.

As these projects always go, we needed to return to West Marine for crimping a few days later when we wired in our solar charge controller. We went to a closer West Marine store this time, and they had a different crimper that wasn’t quite as nice.

Using a hand crimper to crimp ring terminal onto battery cable

This wire is so thick you need a huge wire cutter!

Mark wasn’t as confident that these crimps were as good electrically as the ones made with the first crimper, even though we couldn’t pull the lugs off the wire. So he fluxed the wire and used a propane torch to flow solder into the connection. This way we had not only a solid physical connection but an excellent electrical connection as well.

Soldering ring terminal crimp on battery cable

Mark flows solder into the connector to make a superior electrical connection.

Then he slipped shrink tubing over the connection and used a heat gun to shrink it in place.

Heat gun shrink wrap over ring terminal on battery cable

Shrink tube covers the whole connection, and a heat gun tightens it up.

After our installation, we discovered that Camco makes 2 and 4 gauge battery cable and you can get them here.

Back at the RV, Mark wired the batteries up. He placed the batteries in the battery box bottoms to keep them from sliding around and put the battery box tops on as well so that if anything fell over in the basement while we were driving, it wouldn’t accidentally land on the battery terminals and short something out. We keep that area clear, but you never know when you’ll hit a huge bump and things will go flying.

Trojan Reliant AGM 6 volt batteries in fifth wheel basement

The batteries are ready for their battery box tops.

The AGM batteries do not need to be vented, so he removed all the vent flex hoses. This gave us much better access into the fifth wheel basement from the front hatch door.

Trojan Reliant AGM 6 volt batteries in fifth wheel RV battery compartment

The new batteries are installed, wired and labeled.

Without any flex hose behind the louvered vents, dust and road grime could now flow into the basement, so Mark removed the vent covers and placed a piece of solid plastic behind each one.

Replacing battery vents on fifth wheel RV

The louvered vents are open to the basement in the back and will let dust in.

RV battery vent

Mark puts a thin plastic sheet behind each louvered vent to keep dust out.

We then went on to wire in our new converter, inverter and solar charge controller (installations to be shown in future blog posts).


The performance of these new batteries is nothing short of outstanding. We are floored everyday by how quickly they get charged, and not one bit of corrosion has appeared anywhere.

Mark is happy not to have to check the electrolyte levels in the batteries any more or to remember to equalize them every month. The new AGM batteries are winners all around.

RV battery boxes in 5th wheel basement

Even though AGM batteries don’t have to be installed in battery boxes,
ours are because our basement is large and open and we want to protect them from falling objects!


Our Trojan T-105 wet cell batteries worked just fine for us for years, and flooded are actually advantageous over AGM batteries in two significant ways:

  1. Flooded batteries are much cheaper than AGM batteries.
  2. Well maintained wet call batteries can be cycled more times than AGM batteries

Flooded batteries cost 30% to 40% less than AGM batteries. This can add up to a savings of hundreds of dollars. Depending on the value of the RV or boat, it just may not make sense to have a huge investment in batteries on board.

Also, perfectly maintained wet cell batteries can be cycled more times than AGMs. “Perfectly maintained” means staying on top of equalizing the batteries to keep the battery plates clean and also checking each cell in each battery regularly to ensure that the electrolyte is completely topped off with distilled water at all times.

Under these ideal conditions in the laboratories at Trojan Battery, the Trojan T105 flooded batteries can survive 1,200 cycles where they are discharged to 50% (12.06 volts) and then fully recharged. The Trojan Reliant T105-AGM batteries can survive only 1,000 cycles.

Of course, battery cycling in real world conditions is very different than in laboratory conditions. The degree to which RV and boat batteries are discharged and recharged day to day is far from regular (partial discharging and partial recharging are common). Also, batteries on RVs and boats that are left in storage for any period of time can be difficult to maintain and may degrade despite good intentions (like ours did).

So, the ultimate performance and value of flooded versus AGM batteries is going to vary widely from one RVer or sailor to the next. However, for us, we will not be going back to wet cell batteries any time soon!

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RV Refrigerator Replacement – How an RV Warranty Saved Our Bacon!

We’ve been reporting on whether or not an RV warranty is a good investment for RVers, and this page — the second of four installments — presents our latest findings.
(Hint: the answer is a resounding YES!)

Ten days ago, after a fabulous two weeks in Maysville, Kentucky, and a long day of driving, we set up camp, grabbed a beer, and kicked back to enjoy a cold one. But to our dismay, the beer was kinda warm. We ratcheted the RV refrigerator up a notch and went about our business. After dinner and a movie in our RV, we decided to have a bowl of ice cream. When Mark lifted the lid on the Haagen Dazs, what he found inside could only be described as cool chocolate soup.

Oh no! Our 8 year old RV refrigerator had died.

RV extended warranty repair RV refrigerator replacement

Do something quick! We’re going to lose everything in the fridge and freezer!!

As the clock neared midnight, we began a frantic search for RV repair shops in the area. We put together a list of them, went to bed quite distressed, and first thing the next morning we started making phone calls. Mark threw bags of ice in the fridge and freezer and we didn’t dare open either door after that. We lamented sadly that all our frozen meats — all those nice burgers and steaks, and even our bacon, darn it — were quickly defrosting.

After about 15 phone calls, we were still nowhere. Everyone told us it would be a two week wait to get a fridge and that it would probably cost upwards of $1,500. Finally, we called Camping World just south of Indianapolis. They had an identical unit in stock and they could squeeze us in for service the next morning. They told us they always try to make an extra effort for desperate travelers passing through.

Well, we weren’t exactly passing through. We were in Kentucky driving west towards Tennessee, and they were 150 miles to the north in the totally wrong direction. But what can you do? We were absolutely thrilled to find an RV repair facility that had an RV refrigerator in stock and could install it quickly, so a 150 mile detour was not a problem!

This would be our second major repair in just over a month. We had just had our 36′ fifth wheel trailer axle replaced. What’s worse, we were actually on our way to an RV repair appointment in Kansas to fix a leak in our fresh water tank. What kind of luck was that?

As it turns out, Lady Luck was following us very closely. Our RV extended warranty had covered the bulk of the trailer axle repair, and we were pretty sure it would cover this one too.

Where we stood on our trailer warranty at this point was the following:

We were 11 months into a 4 year RV extended warranty
Cost of RV warranty: $1,904
Reimbursements (less deductibles) to date: $1,036
Remaining Reimbursements to Break Even: $868

You can see the current status of our warranty HERE.

It looked like this RV warranty repair would not only bring our total reimbursements to the point of covering the original cost of the RV extended warranty but would go well beyond that.

18 hours after we’d discovered our fridge was dead, Camping World service manager Rick Helvey was in our trailer examining its hulking carcass. He told us that propane RV refrigerators typically last only 10 years.


It was no surprise to him that our 8 year old unit had kicked the bucket. He opened the fridge vent on the outside of the trailer and showed us the telltale signs of a dying RV refrigerator: greenish or yellowish dust.

The presence of this dust meant the ammonia was leaking out and the cooling unit had given up the ghost. The crazy thing is that the price of a cooling unit is nearly the same as the price of a new RV refrigerator — Not Cheap!

RV warranty repair on a refrigerator - inside the vent

Yellowish dust in the fridge vent area is proof positive that the fridge is dying.

RV warranty repair RV refrigerator installation

Here is a closer look at the greenish – yellowish dust.

He called our warranty provider, Portfolio Protection, to get approval to proceed with the repair the next morning. To his astonishment (and ours), they said they wouldn’t reimburse us for a replacement refrigerator. They would reimburse us only for the replacement of the cooling unit to save themselves a little money. Here’s the breakdown:

Install New RV Refrigerator Parts: $1,389.99
Labor: $267.00
Tax: $97.00
Total: $1,753.99
Replace Cooling Unit Only Parts: $1,049.00
Labor: $356.00
Tax: $73.43
Shipping: $100.00
Total: $1,578.43


This was a problem — for us and for Camping World!!

If we got our refrigerator replaced, we would be in and out of Camping World in 3 hours the next morning and they could go back to business as usual with their local customers. If we had to have the cooling unit replaced, we would have to wait a week or two for the part to come in and Camping World would have to reshuffle their appointments the next morning, once again, because our appointment was already on the books. We had all assumed the approval of a replacement refrigerator would be a slam-dunk.

New RV fridge ready for installation

Our new refrigerator is ready and waiting — all we need is approval to install it!

What to do?

Well, here’s one reason we are becoming more and more enamored of our RV extended warranty through Wholesale Warranties. Unlike most warranty brokers who wash their hands of the deal once you’ve purchased the contract and signed on the dotted line, they are willing to go to bat for you if the warranty reimbursement process isn’t going as smoothly as it should.

We called Wholesale Warranties and told them what was going on. The difference in cost between repairing and replacing was not astronomical. Couldn’t the warranty company allow us to go ahead with the refrigerator replacement?

Within an hour they had called our warranty company, Portfolio Protection, explained to them why it made more sense for everyone involved to install the new fridge Camping World had in stock and, magically, our refrigerator replacement had been approved. We were floored that Wholesale Warranties would do this and that they could be such effective facilitators. Yet it turns out that making these calls is business-as-usual and is routine customer support for them.

Early the next morning we parked the fifth wheel in front of Camping World, and service technician Raymond and his assistant José got started on it right away. Unfortunately, our old refrigerator was 1/4″ too wide and could not fit through our front door. RV refrigerators are installed at the factory before the doors and windows are in place!

RV warranty repair Removing RV refrigerator from fifth wheel trailer

Good heavens, the old fridge can’t go out the front door!

So, the dining room window had to come out!

RV extended warranty Removing an RV window from fifth wheel trailer

The dining room window has to be removed
so the refrigerators can be hoisted in and out.

RV extended warranty repair RV window removed

It would have been so much easier if the refrigerators could have gone through the door!

RV warranty refrigerator replacement gets through window

The new fridge is ready for some strong person to pick it up!

A forklift was used to remove the old fridge and hoist up the new one. It was at this point that I realized just what a challenging DIY project this would have been for Mark!

RV warranty refrigerator replacement New RV fridge on forklift

Thank goodness for fork lifts! This is not an easy DIY installation for one guy!

Then the new RV refrigerator was put in place.

RV warranty repair New RV refrigerator installed in fifth wheel trailer

Raymond settles the new refrigerator into place.

The pretty oak panels from our old refrigerator were slipped into place on the new door.

Under warranty Oak panel installed on RV refrigerator door

Our oak panels from the old fridge slide neatly into place.

Then Raymond ran around back to hook everything up in the refrigerator vent.

RV extended warranty repair new RV refrigerator installation

The back of the new fridge is exposed in the vent area where Raymond hooks it all up.

Meanwhile, his assistant José removed the silicone remnants from the wall around the window opening using a scraper and wiping the wall down with Acrysol

Removing silicone seal on RV window

José scrapes the old silicone sealant off the outside wall
around the window opening.

Removing silicone from RV window

The wall has to be completely clean for a good seal on the window.

Raymond lifted the window into place, and he and José screwed it in place.

RV warranty refrigerator replacement Installing RV window

Raymond puts the window back in place.

Installing RV window on fifth wheel trailer

The guys work together to get the window screwed into place.

Then they remounted the window valence and reinstalled the day-night shades.

Installing valence on RV window

The window valences are reinstalled over the windows.

Installing day-night shades on RV window

The day-night shades are reinstalled on both windows.

Raymond gave us instructions not to put a bead of silicone around the window frame for about a week because he had used caulk tape that would ooze a little for the next few days.

We were impressed with how quickly these guys worked and got the job done, and we were really grateful to Rick for making an opening for us. In just 36 hours from the time we had soup for ice cream, we had a brand new RV refrigerator up and running. Now we just had to wait for it to cool down (about 9 hours).

In the meantime, our frozen meats had fully defrosted but were still cold. We couldn’t re-freeze any of them when the refrigerator finally cooled down. Arghhh!

As we hitched up the fifth wheel, I noticed Mark had a twinkle in his eye as he drove it around to the back lot. He hopped out and instantly set up the barbecue, right there in the Camping World parking lot. He happily began grilling burgers, hot dogs, steaks, chicken and brats.

“We can’t let all this good meat go to waste!” He said to me as he handed me the bacon and sent me inside to fry it up.

It turned out he’d invited the service guys to come on over to our place for a barbecue lunch, and when the yummy smells from our grill began to waft across the Camping World parking lot, they quickly showed up in a golf cart and began chowing down.

The crew enjoys a barbecue lunch

The Camping World service team stops by for an impromptu barbecue. Thank you guys for a super job!

At last it was time to settle up the bill with the service manager, Rick. Our RV warranty deductible was $100. Indiana charges sales tax on deductibles, so our total out of pocket cost for this phenomenal repair was only $107. Wow!!

Our RV warranty (less our $107 deductible + tax) covered $1,647 on this one repair alone — that is nearly the cost of the entire four year RV extended warranty itself!

Shockingly, this RV refrigerator replacement was just one of a slew of major repairs our trailer needed in a four month period in 2015:

Here's a summary of what our four year RV warranty through Wholesale Warranties cost, what our repairs WOULD HAVE cost, and what our warranty reimbursements have been to date:

Cost of Warranty $1,904
Total Cost of Repairs we've had done $7,834
Total Out of Pocket Costs for those repairs $1,145
Repair Reimbursements:
Trailer Axle Replacement $1,036
RV Refrigerator Replacement $1,647
Plumbing Issues & Window Leak $1,142
Suspension Replacement $2,550
RV Toilet Replacement $314
Total Repair Reimbursements $6,689

Our trailer warranty has paid for itself 3.5 times over!
Confused about the nitty gritty fine print buried in RV Extended Warranties? Here's an excellent detailed explanation!!

Are we happy with our extended trailer warranty? OMG Yes!!

Having suffered four major repairs in four months, we have come to the conclusion that anyone with an RV older than four or five years should seriously consider getting an RV extended warranty, especially if they don’t like unexpected financial surprises.

What a shock it was to find out that RV refrigerators are expected to fail by their tenth year of service. All you need is that one repair plus another one or two (air conditioner, water heater, furnace, slide-out mechanism, hydraulic leveling system, etc.) to cover the cost of a four year warranty and even wind up ahead.

Do I sound enthusiastic and excited about our trailer warranty? I am!! I was hugely skeptical about RV warranties before our trailer axle and RV refrigerator replacements, and all I can say is that this has been an amazing process!!

If you want to find out what a warranty would cost for your rig, Wholesale Warranties is offering a $50 discount to our readers. Call our contact, Missi Junior at (800) 939-2806 or email her at missi@wholesalewarranties.com. Or go to this link:

Wholesale Warranties Quote Form

The discount comes off of the quoted price at the time of purchase — just be sure to ask!

To learn how RV warranties work and how they differ from RV insurance, see this article:

What Is An RV Warranty and Is It A Good Investment?

If propane RV refrigerators are so prone to failure, why don’t we have a residential refrigerator? — It takes a huge solar panel array and big (heavy) battery bank to power a residential refrigerator along with everything else in an RV. See the following:

Can a Residential Refrigerator Run on Solar Power in an RV?

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The Full Case History of our RV Extended Warranty:

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Going Full-time – How to Transition & Which RV Is Best?

Traveling in an RV is a blast, and living in one full-time is even more-so. The exhilaration of hitting the open road and discovering the hidden jewels the lie just over the horizon is a peak life experience, and being able to live this way day after day, year after year, is deeply fulfilling.

The transition from a conventional life to full-time RVing can have its ups and downs, however, and there are some pitfalls to avoid and things to consider as you go through the planning process. Just for starters, what kind of RV is best for living and traveling in?

This is the second article in our three-part series on full-time RVing and it explores some of the issues involved in getting from here to there. The other two articles are: Working and Living in an RV and Full-time RVing Tips – Mail, Domicile, Insurance, Saving $$?


For easy navigation on this page, and to read a little now and come back for more later, click on these links:

Links to the entire series and its various chapters are here: Full-time RV Lifestyle Tips

Going full-timg rving motorhome class a towing a trailer which rv to buy

A classy Class A motorhome tows a matching utility trailer in the Arizona desert



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Full-time RVing includes a wide range of lifestyles, from folks who travel a lot to folks who stay home.

Part-time RVers

Many “full-time” RVers are technically “part-timers,” living in their rig for a few months a year and maintaining a home somewhere.  This is a great way to go if you can afford to have both a house and an RV, especially if you can leave your home under the watchful eye of a friend.

For most of these RVers, the travel routes are pretty much north/south.  After spending the first months of our first winter in southern Arizona, meeting people from Idaho and Montana, we were amused to go to South Padre Island Texas and discover many of the RVers were from Wisconsin and Minnesota.  Everyone we’ve met in Florida seems to be from Michigan or the Northeast!

As a side note, if you are looking to simplify your life as well as travel, splitting your time between two homes like this can be a little complicated, as you have either a house or an RV that is always vacant and will need some TLC when you leave it and return to it.

Heading down the highway in an RV

There’s nothing like hitting the open road!

Full-time RVers With a Home Base

A lot of full-timers don’t actually travel 12 months a year.  Some rent or own a site in an RV park somewhere for part of the year, using this location as a home base and roaming around as the spirit moves them. 

Seasonal RV park rates are reasonable, and some parks include a storage area for boats and ATVs or even an alternate RV like a “weekending” or “summer travel” truck camper. Some of these parks also allow you to spread out to do repairs on the RV and clean it up after a season of travel. 

Some full-timers split their time between two RV parks where they have sites they rent or own. Many RVers work camp in a northern location in the summer and in a southern location in the winter.  These types of full-timers have a strong sense of home and community because they return to the same places year after year.

Full-time RVers Who Travel All the Time

Many full-time RVers wander all over the place, more or less in perpetual motion.  Some camp in state parks and forest campgrounds or boondock most of the time, and others stick to RV parks which have more amenities.  Some belong to campground membership programs, giving them a primary resource for finding places to stay, and also giving them a rich social life as they make friendships within the programs and plan their stays to coincide with their friends’ stays.

Full-time RV Residents

Some full-time RVers stay in one park year-round. A few of these folks are retirees who no longer wish to travel but want to remain in their RV. Others are younger working people that have a full-time job in the area that keeps them rooted in one spot.



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Starting a full-time RV lifestyle is an absolute thrill. Leaving the bonds of a conventional life to live in total freedom made both of us feel vibrantly alive. Years ago I wrote a blog post about why we decided to go full-time, called Why Do It? I outlined the many reasons we decided to leave our old lives behind and try a life of adventure on the road.

Going full-time sounds great, but there can also be some bumps in the road on the way to your dream RV lifestyle, and that’s to be expected. The whole process may go swimmingly and you may live happily ever after. But more than likely you will experience some heartache on the way. We did. It’s part of what happens when you deal with important things like Lifelong Dreams, Personal Growth, Enrichment and Fulfillment.


The downsizing process can be intense, especially if you are emptying a large house that you have lived in for years. Keeping your dream alive and priorities straight during this (sometimes) stressful time is really important. When we downsized a second time as we moved off of our boat and back into our RV, I wrote a post On the Road to Your Dreams, Stay the Course to help me keep the big picture in mind.

Vintage station wagon towing trailer

Ready for adventure!

For a lot of people, downsizing all the way into an RV is a really liberating experience. After the hard part of sorting through everything, there is an uplifting sense of relief and unburdening that happens when you let most of it go.

Retiring and Going Full-time Simultaneously

Many people begin full-timing at the start of retirement. This means they are going through two major life transitions at once. Simply changing from the workaday life to one of an agenda-free retirement is a shock to the system. Downsizing into an RV and moving away from old friends and life structures at the same time can become a little overwhelming.

Retiring early is a super idea, but there is no badge of honor for going full-time. In some cases it might make sense to enjoy retirement for a little while first. Going on some shorter duration RV travels before you jump ship all together might accomplish the same travel and freedom goals without giving up the security of everything you know right away.

Life Partners

At the same time as all of this, you are dealing with your life partner in a whole new way. You are together much more than you used to be and are suddenly dependent on each other in ways you’ve never been before. Learning how to operate the systems in the RV, navigating unfamiliar roads in a hugely oversized vehicle in traffic, and getting in and out of RV sites with an audience watching can put a lot of stress on a relationship.

Loving couple in the moonlight

What a marvelous night for a moondance…

To diffuse the tension a little, revel in acquiring new skills, whether it’s learning to read a map or learning to take directions from your spouse as you drive. Respect and patience go a long way as you both adjust to new daily patterns, and in the darkest hours, remembering why you fell in love in the first place always helps. Any scratches that appear on the RV as a result of your joint learning curve can always be repaired!

Build Up and Let Down

There is a huge build-up to the Day of Retirement, and even if you are 30-something and are starting full-timing, there is an even bigger build-up to the Day of Driving off to a New Life in an RV. Some kind of let-down is only natural.

There is also the shock of reality. The RV life depicted in blogs (including this one), books and magazines (including articles I’ve written) may not reveal some of the more mundane and even yucky aspects of life on the road. For us, this lifestyle is almost entirely one of wine and roses, but roses do have thorns and you have to learn to deal with them.

You may be ecstatic when you cast off in your new life, and you may be Living The Dream right from the get go. But if not, don’t panic. There’s an adjustment phase and a learning curve that most new full-timers go through.

Full-time RVing

It takes time to figure out your travel style and what works best for you.

Pacing Your Travels

It’s really common for new full-timers to drive thousands of miles to dozens of destinations at a breakneck pace the first year. We sure did. Heck, you’re excited! You’re free! You run around like crazy! And then you drop from exhaustion.

Learning to slow down and to alternate the sightseeing days with the chore days takes time. Allowing yourself to have a few down days of doing nothing so you can absorb all the thrills you just had during some exciting sightseeing days may make you feel guilty at first. But a life of full-time travel can’t be lived like an endless vacation. You’ll wear yourself down to a frazzle!

Embracing A Hobby

It can be exhausting to spend all day everyday either reading travel literature, sightseeing, or writing in your journal or on your blog about all you did and saw. There needs to be something more to life than scrambling from one tourist destination to the next.

Picking up a hobby can help immensely. Our travel lives changed dramatically when we decided to learn photography and learn to write and maintain a website. These are activities that are beautifully linked to our travel adventures, but they are hobbies in their own right too.

Making music, bicycling, hiking, geocaching, running, yoga, kayaking and learning to make videos are other hobbies that fit a traveling lifestyle well and will ensure you feel like you are living a life that is bigger than just being a tourist.

Making music on the road in an RV

Making music is a fabulous pass-time on the road

What If It Doesn’t Work Out?

Even after dodging that mini minefield of possible obstacles on your way to living the RV Dream, you may decide the lifestyle just isn’t for you. What then? Is the fear that this might happen enough to keep you from giving it a try? I hope not!

You already know how to live a conventional life, and that life will always be available to you. There may be expenses involved in returning to it, but at least you won’t look back later and say, “I shoulda…I coulda…I woulda” Instead, you’ll say, “I did it! I lived my dream, even though it turned out not to be a dream I wanted.” More than likely, the experience will lead you to a dream you do want.

Jumping in with both feet

The most important thing to keep in mind throughout the whole transition process is that this is just a phase of your life. It is definitely not for the rest of your life Without a doubt, your full-timing adventure will end some day, and you will probably move on to another lifestyle that doesn’t include living in an RV.

So, set aside any fears you have, and live your dream. The full-time RV lifestyle may not last forever, but the memories will.



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The most popular full-time rigs are Class A motorhomes and fifth wheels. Class C’s, Class B’s and travel trailers are less common. However, it is possible to travel fulltime in just about anything. Some of the happiest people are those that are debt-free in a smaller rig.

All that really matters when you select an RV for full-timing is that it feels like home to you.

The first time we boondocked in Quartzsite Arizona, we found we were neighbors with 150 Alpine motorhomes (worth as much as $400K) on one side, and a guy living out of the back of his pickup truck on the other side. 

Outside of Phoenix we met a couple who were living in a tiny truck camper with no slideouts on the back of a half-ton gas pickup. They had lived in it for two years and they were loving their simple life.

Half-ton pickup truck camper RV

Do you need a huge Class A to have fun full-timing?
Heck no! For two years this has been home for one couple we met.

In Florida we spent some time with a couple in their sixties who had sold their house and been happily touring the country fulltime for the past four years in a popup tent trailer.

The most seasoned veterans on the road have owned a variety of rigs.  The average owner keeps an RV for just three years, and, having purchased three rigs in our first four years of RV ownership ourselves, we were ahead of the curve for a while! 

If you haven’t done much RVing yet, the best way to get your feet wet and figure out what kind of RV you like and what features are important to you is to get a small and inexpensive one and take it on some long road trips:

Go Cheap, Go Small, Go NOW! Have FUN and Learn the RVing Lifestyle in a Little RV

In the end, the bottom line for buying your new rolling home is:

When you walk inside, do you smile and say, “Ahhhh…home sweet home!!” ?

Also, keep in mind that your first full-time RV probably won’t be your last. You can see our progression of trailer upgrades and truck upgrades throughout our full-time RV travels here:

The Rigs We Have Used for our Full-time RV Lifestyle

Some thoughts about different styles of RVs for use in long term travel:

Both motorhomes and trailers have their pros and cons, and certainly either one makes a fantastic home. These notes are intended to give you some food for thought if you haven’t developed a preference yet. They are not meant to imply that one style of RV is superior to another.

We live in a fifth wheel trailer and have always owned trailers, because we like the look and feel of them, they are simple in their design, and they are fairly easy to understand and repair. Afterall, a trailer is just a box on wheels. We tow our trailer with a big beautiful Ram dually truck. Our hitch is a B&W Companion OEM 5th Wheel Hitch that uses the new in-bed puck system from Dodge Ram (we have a pictorial installation guide for the B&W hitch here).

Motorhomes are inherently more complicated than trailers because they combine the propulsion and the living quarters all in the same vehicle. Higher end Class A motorhomes also feature more complex systems in an effort to make them more like a residential house. Trailers, even high end fifth wheels, are usually outfitted with simpler systems.

Class C Motorhome RV

There’s a big beautiful world out there… Honestly, any rig will be fun!

We have not lived in a motorhome, but our 44′ sailboat was very similar with a combined propulsion/house design and many of the exact same components as are found in a Class A diesel pusher.

Simplicity equates to less time spent on maintenance and repair and less overall expense for everything from initial purchase to insurance and motorhome warranty, to registration to maintenance and repair.

Small rigs:

  • Popup tent trailers are easy to tow, they fit in the garage, and they offer a lot of space for a small package. However, they can’t easily be used to stop for lunch at a rest area or overnight at a Walmart
  • Truck campers and vans make for tight living but can be parked anywhere, from National Park campgrounds to tiny urban roads in the congested northeast.

Travel Trailers and Fifth Wheels:

  • Travel trailers are cheap but can require a bigger truck than you might think to tow efficiently in the mountains (ours did).
  • Fifth wheels are easier to back up and hitch up than travel trailers but generally require a big diesel truck.
  • Fifth wheels are a lot taller and heavier than travel trailers (so you get fewer miles per gallon), and it’s easy to swipe everything off the roof by accident when driving under a low overhang.

Fifth Wheels and Motorhomes:


  • The comfort and view from the driver’s and passeneger’s seats in a big Class A motorhome are far better than in a truck.
  • Tooling around town in a car and getting parked is much easier than in a big ol’ long bed truck.
  • If you are driving a motorhome and need something in “the house,” the passenger can just walk back and get it.
  • Sometimes the huge windshield and large interior space of a Class A motorhome can make for hot driving and you need to run the generator and house air conditioning while driving to cool it down.
  • Gas stations are tough to maneuver in with any large RV. You can gas up a truck when it is unhitched from the trailer. Motorhomes don’t have that option but do have bigger tanks and need gas less frequently.

Fuel Mileage

  • Gas mileage on a truck towing a trailer may be slightly better than on a large motorhome towing a car (especially if the truck has an engine tuner)
  • Gas mileage around town on a car (if traveling with a motorhome) is better than on a big truck (if traveling with a trailer)
  • Depending on how much you drive hitched up versus unhitched, the total fuel bill for a motorhome-car combo may be the same as for a fifth wheel-truck combo (our driving split is 50-50, towing vs. not towing)
Motorhome towing an antique car

To get around town, most full-timers tow a car or “toad” behind their motorhome.
Sometimes the toad becomes a handsome prince and is towed on a trailer rather than its own four wheels.

Maintenance and Repair

  • Larger Motorhomes require a “toad,” or car towed behind, if you want to get around town easily. That’s two engines to maintain — motorhome and car — and the car tires wear as they are towed.
  • Motorhomes are more more complex vehicles than fifth wheel trailers, so they take more time and expense to maintain and repair.
  • A truck with a dead engine can stay overnight in the repair shop while you live in your healthy trailer somewhere else. A dead motorhome engine may leave you looking for a hotel room and eating out if the repair shop won’t let you stay in it there.
  • With a truck and trailer combo, the propulsion part of it (the truck) is mass produced. There are dealerships in every town, and it fits in any repair bay at any shop, including Jiffy Lube.
  • You can change the tires on a truck and trailer with a jack stand and tire iron but will need to call someone for help to change the tires on a big motorhome


  • A truck-and-trailer combo of the same quality, size and age as a motorhome-car combo is generally about 1/2 to 2/3 of the price all together. Insurance, warranty and registration costs are less too.
  • Truck and trailer tires are much cheaper than larger motorhome tires.
  • Oil changes are cheaper, although more frequent, on a truck than on a motorhome

Storage and Living:

  • A large motorhome will likely have a much bigger payload capacity ( > 5,000 lbs.) than a fifth wheel (< 4,000 lbs.) which is important for full-timers carrying a lot of stuff with them. Lots more info on that here: Choosing a Trailer for Full-time RVing – Payload
  • Bikes can be stowed inside a large motorhome bay, or in the hatchback of a “toad” with the back seat removed, or in truck with a cap towing a travel trailer, but they mostly likely have to be left outside on a truck and fifth wheel.
  • While at a campsite, the area under a fifth wheel can provide shade for camp chairs and protection from rain for outdoor goodies.
  • Almost all motorhomes come with a built-in generator which means that air conditioning is available at the push of a button, something solar power can’t easily do.
  • If you love your house but hate how it drives (or it has chronic engine/drive-train problems) or if you love the drive but the house has lost its luster, you can upgrade your truck or trailer independently of one another.
  • There is an urban myth that a motorhome is more appropriate for shorter stays and a fifth wheel is better for longer stays. This year alone, in 8 months on the road, we have stayed at 75 different locations for an average of 3 nights each. We’ve had a ball and it has been easy. We set up and break down in about 10 minutes. I’m baffled by that urban myth, have no idea where it came from, and can only say that it doesn’t apply to us and our fifth wheel! (Wait, what kind of “pacing your travels” was that?! Well, this wild road trip was preceded by 4 months of staying put in Phoenix AZ and included a one month stop in Sarasota, FL)

For a detailed review of what to look for in a full-time 5th wheel trailer, check out this article: Most Important Features in a Full-time Fifth Wheel Trailer

A few things we have learned about buying an RV:

If you are willing to buy used, there are a lot of great deals to be found.  RVs depreciate really fast.  In five years an RV will be worth 50% to 70% of what it was new. In 10 years it will be worth 40% of its purchase price or less.

Negotiate hard. Mass-market brand “vacation” quality RVs often sell for 25-35% less than MSRP and higher-end “full-time” brands often sell for 20-30% less than MSRP, depending on the manufacturer.  The NADA Guide gives the values of used RVs.

If you are buying a trailer, look at the sticker at the hitch end of the trailer on the driver’s side.  This will show when the trailer was built.  If it has been on the dealer’s lot for a while, sitting in the elements (snow, rain, mud, etc.) and enduring lots of foot traffic from customers, there may be a lot of nit-picky problems when you first move in.

The sticker will also give you the payload capacity of the trailer. Many “full-time” trailers are built with a payload capacity of less than 3,000 lbs. In our experience, that will not be enough in the long run. Our fifth wheel trailer has a payload capacity of 3,300 lbs and I sure wish it were closer to 5,000. Here are some thoughts on trailer cargo carrying capacity.

Climb up on the roof of the unit you are buying to see what condition it is in. While you’re up there, check out the other roofs in the lot. You’ll be able to tell which units are the newest ones at the dealership by the condition of the roofs!

We’ve posted a very detailed article that will give you some ideas of what to look for in a full-time fifth wheel trailer. Even if you are planning on buying a motorhome instead of a trailer, many of the same principles still apply. Check it out here!

Visit lots and lots of dealerships and talk to lots and lots of salesmen. The more time you spend shopping the better purchase you will make. Besides, it’s fun!

Here is a video with tips for choosing an RV dealership and an RV salesman: RV Sales Tactics – Understand What You Sign and Don’t Hesitate to Walk Away!.

New Tiffin Allegro Motorhomes for sale

A line of beautiful new Tiffin Allegro motorhomes for sale


Further Reading:

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This was the second part in our 3-part series on full-time RVing. You can read the whole series or skip to its various chapters via these links:

Living and Working in an RV:

Transitioning to Full-timing & Which RV to Buy

Selecting a Domicile, Mail Forwarding, Insurance & Money Saving Tips

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RVing Full-time – Living & Working on the Road

The RV lifestyle is catching on across the country, and there are lots of people who are curious about how to live in an RV full-time. Full-timing is a fabulous way to live, and we have been loving it for years. This 3-part series covers all the basics about full-time RV life, from who’s out here doing it to what to consider when buying a rig for full-timing and how to insure your new rolling home. The other articles in this series are: Full-time RV Tips – Mail, Domicile, Insurance, Saving $$ and Which RV is the Best Rolling Home?

For easy navigation, and to read a little now and come back for more later, use these links:

Links to the entire series and its various chapters are here: Full-time RV Lifestyle Tips

RVing full-time and working on the road

Just another day at the office…what a place to live and work for a season!


“The world is a book, and those who do not travel read only one page.” — St. Augustine, 354-430 A.D.

The first time we learned about the full-time RV lifestyle was in 2006 at Lake Cahuilla Campground outside of Indio / Palm Springs California. We were staying there for a week one February in our popup tent trailer to participate in the Palm Springs Century bicycle ride.  We noticed that every afternoon there was a large gathering of people outside one or another of the RVs parked at the campground.  These folks were all grey haired and whooping it up.  Suddenly we saw an old-timer walking through the campground yelling, “Okay everyone: Time to get up from your naps.  It’s happy hour!”  It was a party on wheels!

We started talking to our neighbors at the campground about how they were living.  Everyone was having a ball and seemed so free.  We heard one woman talking to her adult child on the pay phone, saying “I’ll call in a few weeks to let you know where we are.”  That sounded good to me — I had to be back at work on Monday!  We talked to another woman who was getting a tan in southern California while her friends back in Idaho were shoveling snow.  We heard a few folks making music around a campfire at night.  From what we could see, they lived simply, they had fun with each other, and they seemed happier than anyone we knew at home.

We left California with a new idea taking shape in our minds. 

Our popup tent trailer had become a key to new adventures and a new lifestyle!  We researched what we could online and quizzed the campground hosts wherever we took the popup.  Over time we learned that many people work as they travel, often as “work campers” at various tourist sites.  Suddenly the idea of taking off on a long term travel adventure — with the backup option of getting part-time jobs if we ran out of money — seemed feasible.

We set off on our full-timing adventure within the year!



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Full-time RVers are a rare breed that set out in their RVs for a life of travel.  Many sell their homes, and most have gone through the life-affirming self-discovery process of downsizing all the way to an RV.  They share a curiosity about what lies beyond the horizon, and they are willing to accept a few bumps in the road to find out. The full-timers we have met on the road include the following:


The vast majority of full-time RVers we have met, perhaps as many as 98%, are retired couples.  The average age is mid- to late-sixties, with a lot in their seventies, a few in their eighties and a few in their fifties. Of course, this is the age group that has the money, the time and the lack of day-to-day responsibilities that easily allow for this kind of free-spirited lifestyle. We have read about full-time RVers at both ends of the age spectrum. Many younger full-timers keep fabulous blogs, and some of the oldest old-timers have been written about in the magazines, including a woman who started in 1966 and was still out there in 2008 at age 90, and another fellow who started in 2007 at the young age of 104. We interviewed and wrote a magazine article about a terrific full-timing couple who began in their late 30’s and are still at it in their sixties.


There are quite a few singles on the road. We have run into the Wandering Individuals Network or WINS groups quite a few times over the years. They are a very active group of singles that has a great time together. Another group is Loners on Wheels. If you are a member of Escapees RV Club, you can join their Solos Group. We have camped near them quite a few times in Quartzsite, Arizona.

Surprisingly, we have met lots of women traveling alone.  These gals are strong! A popular group for women RVers is Sisters on the Fly, which is open to any woman with an RV who wants to spend time with other women with similar interests, whether they are single or married, full-timing or not. 

Sisters on the Fly RV club for women

The “Sisters on the Fly” have a ball on gals-only RV adventures.
Many of them have wonderfully decorated vintage trailers!

We have also met two men who had full-timed with their wives until their wives died unexpectedly.  Deeply saddened and lonely, both men opted to downsize from a fifth wheel to a truck camper and continue traveling.  We also met a solo woman who had lost her husband and decided to keep going, big RV, towable boat and all!

Families and The Under 50 Crowd

There is a growing interest in full-time RVing among younger folks, and there are many great blogs by younger RVers who are working on the road. Technology is making it possible for people to have a professional career without having to show up at an office every day.

We have read and heard about these fortunate people, but have met fewer than five on the road since we started RVing full-time in 2007. The youngest full-timers we have met personally was a couple in their early thirties. We’ve also met a handful of couples in their forties. We’ve met one family on the road, a French couple in their late forties with a 3 year old son. They were in the second year of a seven year RV trip around the world! Friends of ours from before our RVing days set off in a 24′ travel trailer with their three kids in 2016 and they have a YouTube channel filled with fun videos of their travels.

The Xscapers branch of Join Escapees RV Club is dedicated to this growing group of younger RVers. Two websites dedicated to families living on the road are: Fulltiming Families and Families on the Road.

The online world of exciting blogs and social media groups related to full-time RVing for the younger set can make it look like there are tons of families and young couples out adventuring in their RVs full-time. This is a wonderful and lovely thought. However, in our personal experience on the road, we have met only an extremely very rare few.



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Campground hosts enjoy sharing insights into their RV lifestyle

An offer of free beer is hard to turn down!

You will learn the most about full-time RVing by
talking to full-timers IN PERSON.

Where can you find them? At RV parks and campgrounds!

Most hosts are either full-timers or part-timers, and they are a wealth of information about every aspect of RVing, from rigs to travel to jobs to living small.

They may also know of other campers staying in the RV park or campground that are full-timers that you can talk to.

There is nothing like the back-and-forth of a real conversation to get all your questions answered quickly and to explore other subjects that suddenly spring to mind.

Before we started, we learned a lot this way. We owe a huge debt of gratitude to Bernie and Phyllis, hosts at Bonito Campground in Flagstaff, Arizona, who talked to us endlessly about trucks and fifth wheel trailers and solar power.

If you feel funny about taking up their time, ask the hosts if you could bring over some drinks and snacks at happy hour and chat with them about the lifestyle for a while. Few people will turn down a free drink and a chance to talk about a lifestyle they love!

You can do this kind of in-person research with experienced RVers whether you are staying in a hotel near an RV park, staying in a tent at a campground or staying in an RV.

Where can you find a high density of RV parks and full-timers? In the southern states in winter! Take a roadtrip to Quartzsite, Arizona, during the Quartzsite RV Show in January, and drive around on all the roads within a 15 mile radius of town. Pitch a tent and go make some friends. Or visit Yuma or Mesa, Arizona, or southern Texas or anywhere in Florida!

Buy A Cheap RV and Go Play!

Another great way to learn about full-timing is to get a smaller, cheaper RV and go try it out. As mentioned above, we started with a popup tent trailer. By the time we hit the road full-time, we were very seasoned RVers and had dry camped in campgrounds over 150 nights. This made it very easy for us to begin boondocking as newbie full-timers and know what to look for in a trailer.

Rental RV - learning how to RV full-time

Renting an RV for a week’s vacation in southern Utah is a great way to sample the lifestyle.

A small used trailer or used Class C or van would work just as well.

This experience will teach you a million things about RVing and about yourself: the kinds of places you like to stay, the kinds of people you’re likely to meet in your travels and how the systems on an RV work, whether you are plugged into hookups or are dry camping somewhere.

You will also learn what you want and don’t want in your full-time rolling home!

Rent an RV and Try It Out!

If you don’t live in an area that lends itself to easy weekend RV travel, then flying to a gorgeous place and renting an RV is a fabulous way to go.

Renting an RV for a week may look really expensive on paper, but the memories will last a lifetime and the lessons you will learn will be priceless.

There are lots of RV rental companies all over North America. Most companies rent Class C motorhomes, and we’ve seen them everywhere in our travels. A few companies to look into that have their own fleets of rental RVs are:



There are also companies that offer rental RVs that are owned by private individuals or are part of smaller RV dealership rental fleets. These companies provide a “peer-to-peer” rental experience and function much like AirBnB and VRBO in the vacation rental property industry.

This kind of RV rental company acts as the middle man between the owner, who is renting out their own RV or one in their fleet, and the renter. The company’s website serves as an “aggregating” searching tool to put these two groups of people together.

This concept is potentially a great boon to both RV owners and to people who want to try out a particular style of RV before committing to buying one. For RV owners, there is a potential to make a few dollars on an RV that is otherwise sitting unused in their driveway. For prospective RV buyers, it is a neat way to try a tear drop trailer or fifth wheel trailer for a weekend and get more of a feel for it than just by looking at it on a dealership lot.

One of the first companies in this industry is RVshare.com.

Of course, both lessors and lessees need to enter into these contracts with eyes wide open, as there is the potential for things to go awry. An unscrupulous owner might be trying to make a few bucks from a junker that has been rusting in the back yard for a few years, or an unscrupulous renter might throw a wild party in someone’s meticulously maintained RV.

Rental RV in the Canadian Rockies

Take a vacation to a beautiful place in a rental RV!

The key to enjoying a happy RV rental, whether from a single source rental company that has its own fleet of RVs or through a website like RVShare.com that brokers deals between individual RV owners and renters, is to make sure you have covered all the bases before signing on the dotted line.

A few things to consider:

  • Have you tabulated all the hidden fees beforehand and do you have them in writing?
  • Do you have a written contract detailing how and when your security deposit will be refunded to you?
  • Do you understand exactly how the unit is insured (many private RV insurance contracts do now cover RVs that are leased out)?
  • Do you have all the codes and phone numbers necessary for obtaining roadside assistance if it is offered?
  • Have you done your due diligence searching for complaints against the company and pondering any negative reviews?
  • Have you contacted previous renters to find out if they were happy with their RV renting experience?
  • Do you have the phone numbers and names of the key people at the rental company so you know who is responsible and who to call in the event of breakdown or a financial concern?

Research the RV Lifestyle Online

In between your weekend and vacation RV adventure travels, there are lots of resources that will help you with your planning.

One caveat about any online discussion group or website where the writers are fairly anonymous is that they may or may not be experts about the topic. Take everything with a big grain of salt and trust your own instincts. I was amazed to find out that a very outspoken member of a popular cruising forum hadn’t sailed in 30 years and lived hundreds of miles from the ocean. Yet he expressed his opinion on every cruising topic. It was his way of feeling connected to a world and activity he loved and dreamed of doing.

Learn RVing with a Popup tent trailer RV

An inexpensive popup tent trailer can give you some incredible RVing adventures



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The full-time RV lifestyle can be very inexpensive or very costly, depending on how you choose to live. We are budget travelers and have posted a detailed explanation of our costs and budget over seven years of full-time travel here:

Full-time RVing Costs and Budget

There are a myriad of options for making money on the road. The range of things available depends largely on how much money you need to make.

We started full-timing before retirement age, however we do not work. We live very simply and we were lucky enough to have a small nest egg before we began our adventures. We set up our investments before we left home.

Consulting Work or Part-Time Work In Your Profession

One approach to working on the road is to take part-time jobs in locations where you want to live for a while. Some professions lend themselves to that. Nurses can get three- to six-month contracts that pay a full professional wage. A couple we know of in the oil and gas industry takes contract work within their profession. We met a young couple that was waiting table at swank restaurants near their favorite national parks each summer and making enough money to float their RV lifestyle all winter. We met a woman who was a contract waitress for a catering firm in Las Vegas and she was doing very well too, bopping in and out of Vegas whenever funds ran short.

We have also met construction workers and electricians who work on jobs for short periods and then move on. If your profession doesn’t lend itself to part-time contracts, you might have skills or a hobby that lends itself to part-time jobs.

Early on, we met a young pair of musicians living in a popup tent trailer for the summer and playing gigs across the country. They booked themselves about 3 to 6 weeks out at various bars and other venues and were having a blast. We heard of a pair of sailors that did the same thing across the South Pacific ocean!!

One strategy is to work a “real” job for a period of time and then travel until the money runs out, and then repeat the cycle. School teachers can travel in the summertime. A ski instructor or sailing instructor can travel in the off season.

Ordinary Part-Time Jobs In Seasonal Tourist Destinations

There are also “help wanted” postings for part-time work in many towns that have a seasonal tourist industry. What fun to work in a boutique shop for a while! Many employers have trouble finding seasonal part-time workers among the local population, and they are happy to hire RVers who want to stay in town for a season.

In Jackson, Wyoming, where the billionaires have pushed out the millionaires, we spotted a help wanted sign in tne window of a fabulous bakery and coffee shop. I asked it they would hire RV travelers for two to three month stints. Absolutely! They loved the idea of mature workers who would be prompt and reliable. In the summer of 2014 they were paying $10 an hour.

Working on cruise ships and luxury charter yachts are another option. Just store the RV for the months you are at sea.


Some RVers come up with a product to sell at the many RV rallies held around the country. Others write books about RVing or their travels or take on some freelance writing. An engineering friend of ours absolutely loves to grill meat, and he was hanging out on his favorite website about barbecuing and grilling one day when he noticed they wanted someone to do scientific testing on grill thermometers. He made $8k last year testing thermometers for them. Who woulda thunk??!!

Transcription work can pay really well. Full-timer Wendy Estelle explains the details on her blog, Gypsy Gibberish, HERE.

Another popular occupation for RVers is to work for the company that provides the free RV campground maps that you get when you check into a park, AGS Guest Guides. These maps/guides are paid for by the advertisers whose ads appear on them, and AGS Guest Guides hires reps to go out into the community to solicit ads. From what I understand, reps can stay in the RV park for free for as much as two weeks while they meet with the advertisers and get to know the area. More info here: AGS Guest Guides.

Many people dream of making money on the internet from a blog, or some sort of web service, or from online product sales. This is highly competitive, however, as everyone in the world wants to stay at home and make money on the internet, whether or not their home is an RV.

RV travel blog writing

Is an RV blog a good way to earn a living in the road?

So, can an RV blog support your travels? Our blog has given us priceless experiences and opened some wonderful doors and given us some great opportunities that wouldn’t have been possible otherwise. For cold, hard cash, however, a “real job” (flipping burgers) would pay far more per hour for the first few thousand hours. I explain a bit about how all this works in this post: In the Spirit of Giving.

I’m hardly an expert on travel and RV blogs, however, and my experience is limited. A far more experienced blogging couple, both of whom work on activities related to their blog all day every day — and theirs is one of the top travel blogs in the entire world — has this to say on the subject of making money from a travel blog: I Want To Know Your Secret

In a nutshell: if you need to earn cash on the road to make your dream of a full-time RV lifestyle come true, the bottom line is to get creative. What do you love to do? How would you like to spend your days?


Work Camping – What Is It and How Do You Find Out About Job Openings?

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Work camping is part-time work that is geared specifically towards RVers, often including an RV site on the jobsite or nearby as part of the compensation or at a reduced rate. Work camping is super popular with full-timers, and many choose their destinations based on work camping opportunities. Most of them seem to love their work.  If you don’t need a full-time job to cover your expenses but do want a little supplemental income or want to work in exchange for a “free” RV site, this is a great way to go. 

RV Work camping can be lots of fun

A very happy work camper on the job

The best workcamping options, according to the workcampers we have met on the road, are often found either in private deals or at small out-of-the-way places.  One workcamper who has been at it for over 15 years told me that his favorite places were small historic sites. 

Another workcamper we met on the Oregon coast was assigned the task of distributing literature to beach-goers about a rare plover that nested in the dunes.  He loved birds, and these plovers were interesting little creatures.  What a fun way to keep the public informed about an unusual bird and get an RV site with full hookups in exchange.

A good arrangement I heard about was a very wealthy absentee estate owner who needed someone to mow the lawn once a week.  The estate owner had installed RV hookups and the work camper lived on very plush grounds for a few months in exchange for mowing the lawn and “being a presence” on the property. 

Some private RV parks pay a good wage for workers that can maintain the grounds, check people in and out, etc. We’ve heard of pay rates as high as $20,000 for a couple, each working 25 hours a week, for six months. One of our readers told me about a fabulous job she has manning the guard shack at an oil field. The work is easy and the pay is terrific.

Work campers at the Escapees CARE Assisted Living facility in Livingston, Texas, receive meals as well as an RV site, and they get a discount on future stays in other Escapees RV parks to boot.

In Mesa, Arizona, where thousands of snowbird RVers flock each winter, we met two couples work camping at a cute little bakery called RaVeS Cafe. It has an RVing theme and is adorably decorated with RVs and RVers in mind.

At stunning Bryce Canyon National Park, in Utah, the privately owned hotel, gift shop and restaurant complex that is located just outside the park, Rubys Inn, has an RV work camping program that we’ve heard great things about as well: Rubys Inn Employment.

RV cafe RaVeS for RVers and RVing

Work campers at RaVeS Cafe in Mesa Arizona

And, of course, some people work camp not because they need the cash but because they want to give back to society. There are loads of opportunities through the National Park Service, US Forest Service, BLM and Army Corps of Engineers.

One really fascinating workamping volunteer position we discovered was cataloging ancient Indian pottery for the National Park Service. This job was described to us by our vivacious tour guide on a ranger-led tour we took of the ancient Indian ruins at Tonto National Monument in Arizona: Workamping with the Ancients at Tonto National Monument

Another very popular program designed specifically for RVers is Amazon Camperforce where you can join dozens of other RVers at the big Amazon warehouses during the holiday season, packing boxes and shipping products, and make some really good money while you’re at it.

Websites that list work camping positions include the following:

Things to Ponder About Work Camping

We have not work camped yet, but we have met a lot of people who have. Listening to their stories prompts these thoughts:

— Choosing a work camping position is a hunt both for property and for a job. Not only do you need to make sure you want to do the work that’s required, but it needs to be in a place where you want to be, both on the map and within the grounds of the location.

— Sometimes work campers are given a yucky site next to the dumpster out back. Sometimes they are required to work 35 hours a week instead of the advertised 20 hours a week they saw when they took the job. The National Parks subcontractor Xanterra has been notorious for offering poor work and sub-optimal RV sites for minimal pay.

On the other hand, we’ve met RVers work camping at state park campgrounds on the waterfront in San Diego that keep going back and back and back again because they love it so much.

Mark plays air guitar with his rake

Raking is fun but taking a break to play air guitar is even more fun!

— Whatever kind of part-time work you take, whether in your professional field or work camping at a National Park, it is important to evaluate both the work required and the wage being paid to make sure you feel the exchange is fair. If you are trading labor for a site, make sure the site and the hours of labor you are paying for it match up with other RV park sites in the area — or that you are happy with the trade.

— For many retirees, there is nothing more fulfilling than helping out at a national or state park, and the positions can be in the gift shop, at the front gate, on the grounds or in the bathrooms. We met an 81 year old whose RV site at a national forest campground without hookups would have cost him just $3 a day if he didn’t workcamp there. However, he was more than happy to put in 8 hours of work a day picking up trash for four full months. He made a massive contribution to the area, and was sorely missed when his workcamping stint was over. He sure wasn’t being paid fairly, but he was one happy camper!

— For younger folks that need a living wage, the step down from a professional white collar position to cleaning the bathrooms at a private RV park can be a big jolt. Sometimes the bosses don’t remember you had a fancy career and they treat you like grunt labor. It’s important to think all this through before ditching a good paying conventional job and a big house mortgage to live in an RV and bounce from RV park to RV park doing menial work.

Fortunately, there are many kinds of work camping opportunities, and judging by the number of very happy work campers we have met, it is definitely a viable option to flush out the travel kitty and reduce camping costs.

Further Reading:

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This was the first part in our 3-part series on full-time RVing. You can read the full series or skip to its various chapters via these links:

Living and Working in an RV:

Transitioning to Full-timing & Which RV to Buy

Selecting a Domicile, Mail Forwarding, Insurance & Money Saving Tips

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What Is An RV Warranty – Do You Need One? Is It A Good Investment?

An RV Extended Warranty (or “RV Warranty“) is a mechanical breakdown protection product that you can purchase for your RV to give you a financial boost in the event that a system on your RV suddenly fails. By their very nature and reputation, RV warranties are contracts that most RVers either swear by or swear at, and for those of us whose eyes glaze over when reading legal documents, it can be really hard to figure out whether or not buying an RV extended warranty is a worthwhile investment.

This article is the first in a series of articles about RV extended warranties that present our personal case history with our RV warranty on our 2007 NuWa Hitchhiker II LS fifth wheel trailer (four year warranty cost: $1,904). This first article begins by explaining what RV extended warranties are, how they work, and how they differ from RV insurance. It also explains what to look for when buying an RV extended warranty contract. Then it goes on to show our own RV warranty in action during our first claim which was an axle replacement on our fifth wheel trailer ($1,136 reimbursement).

The rest of the articles in this series show our warranty in action. How valuable is this extended trailer warranty to us?

Here's a summary of what our four year RV warranty through Wholesale Warranties cost, what our repairs WOULD HAVE cost, and what our warranty reimbursements have been to date:

Cost of Warranty $1,904
Total Cost of Repairs we've had done $7,834
Total Out of Pocket Costs for those repairs $1,145
Repair Reimbursements:
Trailer Axle Replacement $1,036
RV Refrigerator Replacement $1,647
Plumbing Issues & Window Leak $1,142
Suspension Replacement $2,550
RV Toilet Replacement $314
Total Repair Reimbursements $6,689

Our trailer warranty has paid for itself 3.5 times over!
Confused about the nitty gritty fine print buried in RV Extended Warranties? Here's an excellent detailed explanation!!

What is an RV Warranty and should you have one?

To buy or not to buy an RV warranty?

You can navigate through this article using these links:


RV Extended Warranty Overview

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All RVs come with a manufacturer’s warranty when they are purchased new, and these warranties are good for a year or two.

After the manufacturer’s warranty expires, you can purchase an RV Extended Service Contract, commonly known as an RV Warranty, from an independent warranty company for another few years. Or you can just hope for the best.

RV extended warranties are contracts that describe in detail what is covered and what is not covered by the policy, and they have a specific start date and end date. You can pay for the warranty outright when you sign the contract or you can purchase it over time with payments. These contracts are designed to cover the mechanical working components on and in your RV.

If you have an RV extended warranty, when there is a system failure on your RV, you begin the process of filing a claim with your warranty provider by finding an RV repair shop of your choice to diagnose the problem. The shop then calls the warranty company’s administrator for authorization to do the repair. The claims adjustor then reviews the details of your failure to determine if the failure falls under the coverage offered by the contract you purchased. After a covered repair is completed, the RV repair facility contacts the warranty company to present them with the bill, and the warranty company pays for the covered items immediately with a corporate credit card. You then pay for the items that were not covered by the warranty plus a deductible.

The real sticking point comes with what is covered and what is not covered by the warranty. It is up to you to determine the likelihood that enough items on your RV will break during the time period that the warranty is in place to cover the cost of the warranty. Obviously — and hopefully — it will cover a bit more than that, just to make you feel like you made a smart decision by buying a warranty in the first place.

What Is The Difference Between Insurance and A Warranty?

In a nutshell, the difference between an insurance policy and a warranty is that insurance covers damage caused by an incident or accident happening, while a warranty covers the failure of something mechanical that shouldn’t have broken.

Insurance is there for damage that can be pinpointed to an event on a particular date: a fire, a theft, a tree falling on the rig, a tornado. Warranties are there for systems that die without an obvious cause: the hot water heater can’t warm the water any more, the fridge can’t keep the food cold any more, the air conditioning is on the fritz, or a slideout room refuses to budge in or out.

Insurance is something we all understand pretty well since we’ve all had to have car insurance since we bought our first car. Warranties are a little less familiar because, for most of us, our only experience is with manufacturers’ warranties or with a home warranty we got as part of the deal when buying a house. There are no laws that say we have to purchase a warranty of any kind for any big asset we own, so many folks (like us) steer clear of them!


The value of an RV warranty all boils down to risk. Just like insurance, you pay some money up front in the hopes that something major goes wrong that will cost a lot more than the money you paid for the contract. It’s a way of protecting yourself from having to come up with a massive amount of money to pay for an unexpected repair — a way of hedging your bets by paying a little now instead of (possibly) a lot later.

Just like playing the slot machines at the casino, you put in quarters — either with regular payments or by paying for the whole contract at the beginning of the warranty — and you hope the bells suddenly go off and a huge pile of quarters lands in your lap. Unfortunately, in the back of our minds, we all know that when it comes to casinos, “the house” always wins. And who owns the biggest and fanciest office buildings in most major cities? The insurance companies!

So, while we consumers are betting that something bad will happen when we buy insurance or a warranty, the insurance and warranty companies are successfully betting that it won’t.

Our RV warranty Personal Case History

RV extended warranties provide the most value for folks that have a rig that is two or more years old. Our fifth wheel trailer that we live in full-time is a 2007 model, and its aging equipment could be very costly to repair. The hot water heater, RV refrigerator and air conditioning systems are all more and more prone to failure as the days pass. Sometimes older rigs like our develop cracks in the frame or the big slide-outs fail (we have three slides). We’ve heard heard horror stories from fellow RVers of broken trailer axles and unexpected $1,700 refrigerator replacements. We realized that an RV warranty could make a lot of sense for us.

As we did our research, we had no idea that we would soon experience both trailer axle AND RV refrigerator failures!

We decided to work with Wholesale Warranties, an RV extended warranty broker. We gave them the details about our rig, and they got quotes from the warranty companies they work with and chose the one that was best suited to our situation. We signed a contract with Portfolio Protection for a $1,904 four year Exclusionary RV Extended Warranty with a $100 deductible.

Fifth wheel trailer RV at Harvey RVs in Bangor Maine

Our fifth wheel peeks out from the its hospital room at Harvey RVs in Bangor Maine

Some warranty companies are fly-by-night operations that might go out of business before the contract period ends, and others have top ratings with the Better Business Bureau and are backed by A-rated insurance companies that will step in and take over if the warranty company fails.

Wholesale Warranties makes it their business to sort out which companies are the best ones and to establish relationships with them. Wholesale Warranties has been growing by leaps and bounds and was named one of Inc 5000’s Fastest Growing Companies in 2014, and one of San Diego’s fastest growing companies in 2015. More important, they have made many clients very happy.

What is unusual about Wholesale Warranties is that they don’t simply sell a contract and walk away. They are there for their clients to help smooth the process, if necessary, when a claim is filed. In fact, they are willing to pay for a client’s claim themselves, if they believe it was wrongly denied, and then fight with the warranty company behind the scenes after the fact.

Little did we know that before the first year of our contract was up, we would need FOUR major repairs on our trailer and we’d end up almost $4,500 AHEAD of the cost of our trailer warranty!


The RV Warranty In Action – Trailer Axle Replacement!

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About three weeks ago, in mid-July, 2015, Mark noticed some serious and irregular wear on the passenger side tire on our rear trailer axle. Our tires were just 14 months old, had been properly cared for, and had less than 10,000 miles on them. Oddly, one half of the tire had okay tread while the opposite half, 180 degrees out, was a mess. On the bad half, the tire was severely cupping on the outside tread and was nearly bald. The other three tires looked great. Much research and many phone calls later, we realized that our problem was probably a bent axle.

Bald tire

Weird tire wear: bald on one side, on one half of the tire

Bald tire other side

Same tire spun 180 degrees – bad but not bald!

We were wrapping up our travels in Nova Scotia at the time. We weren’t sure what was involved in replacing an axle, and even though our warranty covered repairs in Canada as well as the US, we had friends in Bangor, Maine, and felt better about doing the repair there. Lippert Components helped us locate a phenomenal RV repair facility in Bangor — Harvey RVs — and we nervously drove 450 miles to Bangor on the faulty tire and took the buggy in.

The diagnosis was exactly what we had expected: a bent axle. The bizarre wear on the tire was due to the tire “dribbling” like a basketball as it rolled down the road. Unfortunately, by the time we got to Bangor, the driver’s side tire on the bad axle was also beginning to cup, and we needed both tires replaced.

We decided to take advantage of our RV warranty to have some other broken items repaired as well. This way, one deductible payment would cover all the different warranty repairs. The extender on one of our awning arms had sheered off, and we had just developed some kind of leak in the fresh water tank during the last few weeks.

Brent Horne, the service manager at Harvey RVs, called our warranty company’s administrator and got same-day authorization to do all three repairs, with the water tank repair pending a full diagnosis.

The axle replacement and awning arm replacement went like clockwork, although we did have to wait ten days for the new axle to be built and shipped from Indiana. A minor complication with the replacement was that the new axle came with electric drum brakes pre-installed and we had to move our new disc brakes from the old axle to the new one.

The diagnosis on the water tank was inconclusive. The leak was at the top of the tank, and we would have to drop the tank out of the trailer frame to determine the cause. Because it was at the top of the tank, it leaked only when the tank was totally topped off, not when it was less than full. We decided to defer that repair to the service folks at the Kansas RV Center (which used to be NuWa, the manufacturer of our trailer) rather than delay our travels waiting for a replacement tank to be shipped to northern Maine. Kansas would be in our general direction as we headed west in the fall.

Old trailer axle new fifth wheel RV axle

The new axle (left) has electric drum brakes and old axle (right) has our nifty new disc brakes.
The challenge with this repair was moving the disc brakes from the old axle to the new one.

When the bill for the repairs came, it was the following:

Awning Arm, tax and labor 46.73
Trailer axle, tax and labor 1,089.42
Freight for trailer axle 219.90
Tires, tax and labor 417.78
Total Repairs: 1,773.83

The Service Manager, Brett, called the warranty company and was immediately paid by credit card for the following:

Awning Arm, tax and labor 46.73
Trailer axle, tax and labor 1,089.42
Total Covered by Warranty: 1,136.15

Our bill was the following:

Freight for trailer axle 219.90
Tires, tax and labor 417.78
Deductible 100.00
Total Out of Pocket: 737.68

So, on a total bill of $1,773.83, our savings was $1,036.15.


RV Warranty Analysis

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As mentioned above, RV warranties are intended to reimburse the parts, tax and labor expenses for repairing system failures, and the trailer axle and awning arm piece were clear system failures.

However RV warranties do not cover the freight costs for shipping large replacement parts from the manufacturer to the RV repair facility, and they don’t cover “maintenance items” that wear out or need regular maintenance to operate correctly. There is also a very large gray area when it comes to items that were damaged by the failure of something else, like the tires being damaged by the failed axle. Similarly, water damage due to plumbing or roofing failures may or may not be covered.

In our case, even though the tires were very obviously disintegrating because of the bent axle, they are classified as a maintenance item so they weren’t covered. We learned later that Wholesale Warranties has a separate policy for tire failures due to road hazards, but it wouldn’t have helped us in this case either.

So, we paid for the tires out of pocket.

Has our RV warranty done the job so far?

Absolutely! 10 months into our 4 year warranty contract, here’s where we stand:

Cost of warranty: $1,904.00
Reimbursed so far: $1,036.15
Remaining to break even: $867.85

We are 20% of the way through our warranty contract period.
We are 54% of the way through our contract cost.

So, we are ahead of the game at this point. $867.85 more in repairs in the next 38 months, and we will have matched the cost of the warranty.

NOTE: We did not know at the time we wrote this that we’d have a bunch more major repairs in the next THREE MONTHS!

A financial breakdown of all our repairs is at the top of this page HERE

Harvey RVs Bangor Maine

All smiles at Harvey RVs after the repair is finished
Expert Technician Steve and Service Manager Brett join me in front of our rolling home.

Could An Insurance Policy Have Done The Job?

Usually, insurance and warranties don’t overlap in the kinds of things they cover. Insurance generally requires an event that caused damage while a warranty generally requires a system to fail on its own. In this particular situation of a bent trailer axle, however, if we could have pinned the axle failure to a particular event, perhaps when we hit one particuarly gargantuan pothole of the thousands we encountered in Nova Scotia, then we could have filed an insurance claim based on hitting that pothole.

Using insurance, our claim would have been:

Trailer axle, tax and labor 1,089.42
Freight for trailer axle 219.90
Tires, tax and labor 417.78
Total Claim: 1,721.10

Note that we couldn’t have slid the awning repair into the insurance claim.

If the claim were approved, all of those items would have been covered. However, we have a $500 deductible on our trailer insurance and we would have had to pay the $46.73 awning repair out of pocket.

Here’s the breakdown for comparable repair work (axle and awning) using our warranty versus our insurance policy:

Covered Out Of Pocket
Warranty 1,136.15 737.68
Insurance 1,721.10 546.73


Why Use a Warranty When Insurance Works Too?

If we had filed an insurance claim, there would have been a wait for an insurance adjuster to assess the damage. With the warranty, the authorization for the repair is given to the service provider as soon as they call. Also, our “reward” for filing the insurance claim would have been a ding on our insurance record which would have affected our insurance premium in the future.

If we had had one of those nifty insurance policies that has a “disappearing deductible” that decreases each year that no claim is filed, the clock would have started over again at the maximum deductible amount the next year after we filed the claim.

I’m not sure if the difference in out of pocket costs of $190.95 ($737.68 in the case of using the warranty minus $546.73 in the case of using the insurance policy) would have been made up in the next three years of insurance premiums (the time period that the warranty will continue to be in effect), but it’s easy to imagine this claim resulting in an increase in our annual insurance premium of $66.67 ($190.95 / 3 years).

Of course, this particular system failure — a bent trailer axle — is unusual in that it is even possible that an insurance policy might have been used to pay for it. In most cases, RV systems die on their own without a specific event causing the failure (an accident, road hazard, theft, etc.), and those failures are not eligible for insurance coverage at all.


Is An RV Warranty A Good Value?

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RVs are notorious for system failures, and sooner or later big expensive stuff is going to break on every RV.

If you don’t like large, unexpected financial outlays, an RV extended warranty can mitigate or eliminate the cost completely when a major system on board goes on the blink. There’s a lot to be said for that when you are suddenly jerked off the road and away from your travels and dumped into the waiting room at an RV repair shop while you nervously wonder if the service guys are any good and if your rolling home is going to be repaired correctly.

Bicycle riding in Nova Scotia Canada

It’s a shock to be dragged away from your happy travels to deal with an RV repair

Obvioiusly, you could simply bank the amount you would have put into buying an RV warranty and use that cash as needed when things fail. It is easy to go that route when you remember that, on average, RV warranties must work out in favor of the warranty companies or they couldn’t stay in business.

However, an intangible in all of this is peace of mind when chaos reins. Abandoning your travels to take care of an ailing RV is really stressful. Believe me! And there are lots of stresses involved in any repair that is big enough to be warranty-worthy.

There is stress in finding a repair facility that has the right equipment and the right skill set and a good reputation, especially when you are traveling in a part of the country you don’t know. There’s stress in taking a detour to get your RV to the shop if it’s not in totally safe driving condition (like ours was). There’s stress in figuring out where you’re going to stay while your RV is in the shop, if you can’t stay in it. And there’s stress as you wait, first for a shop appointment, and then for the necessary parts to come in.

Going through all that stress while also knowing in the back of your mind that the repair is going to put a big hole in your bank account makes it even worse.

Directions to Everywhere

It’s all fine and dandy to be traveling in remote areas,
but where do you find a top quality RV service repair shop?

The purpose of an RV warranty is to pay up front to cover potential costs later. Where they get the bad rap is when you pay up front to cover potential costs that never materialize or that materialize but aren’t covered. However, if you think about it, in many ways the devil that you don’t know may be worse than the devil that you do.

What I mean is that paying a fixed amount for an RV warranty, an amount that you know up front, may save you more or less cash for repairs in the end, but at least you’ve lessened the surprises and you know your costs. Plus, you may save far more than just cash when all is said and done. Even if having the warranty doesn’t save you all the cash you spent on it, you can view the difference as the price of peace of mind. If it saves you more than it cost you, you’re ahead.


What to Look For in an RV Extended Warranty

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It is easiest to turn to a company like Wholesale Warranties to get a warranty. When you work with them they will evaluate which warranty product is the best fit for your RV. Whichever warranty company they recommend for you, one of their requirements is that the warranty company call them if you file a claim that is over $500 so they can be part of the claims process and help it be as smooth as possible.

Since we got our RV warranty (our warranty company is Portfolio Protection), Wholesale Warranties has grown a lot and has begun providing their own warranty protection in addition to brokering for warranty companies like Portfolio Protection. This is a new and exciting development, because they have been through the claims process with their clients so many times that they know what RVers really need. The name of their warranty company is Viking Protection.

However, if you want to research RV warranty companies on your own, here are some things to think about:

Inspection and Age of RV

With the better warranty companies you will need to make your RV available for an inspection to determine the condition of everything at the start of the contract. This way, when you file a claim, there is no question as to whether the problem was a pre-existing condition. The warranty companies that Wholesale Warranties works with will send an agent to your RV, wherever it is parked, to do the inspection, and you don’t have to lift a finger.

If your RV is older than a 2001 model or has over 100,000 miles on the odometer, it may be difficult to find a warranty company. In some cases, a motorhome with more than 100k miles can get a “coach only” warranty for everything except the engine and drive train.

Warranty Types

There are two major warranty types: Stated Components and Exclusionary Contracts. Stated Component contracts cover only what is listed in the contract. Exclusionary Contracts cover everything EXCEPT the items listed. Definitely get an Exclusionary Contract, as many more things are covered in that type of contract.

You Choose the RV Repair Shop

Make sure there’s no clause that restricts who can do the work. You want to choose the best repair facility you can find and not be forced into using one that is not up to your standards.


Deductibles can vary. Make sure you know what it is!

Fair Treatment of the RV Repair Shop

Be sure the warranty company guarantees to pay the RV repair shop quickly, preferably immediately with a corporate credit card, and make sure they pay the shop’s standard prices for the parts rather than wholesale or some amount to be negotiated. RV repair shops are often little outfits, and they can’t afford to be toyed with by a warranty company.

What Happens if the RV is Sold

Be sure the contract will be valid for another owner, just in case you decide to sell before it expires. A warranty is a nice perk to offer the buyer that may set your rig apart from others they are considering.

Cancellation, Missed Payments and Refund

Find out what happens if you decide to cancel the contract prematurely, and whether the purchase price will be refunded in whole or in part, and find out what happens if you miss a payment. Some warranty companies offer a month-to-month payment arrangement, but in the event that you miss a payment the contract terminates. Wholesale Warranties goes the extra mile and will work with you if you have extenuating circumstances that make it hard to make a payment, and if you cancel before the contract is up, you will be refunded the unused portion of the contract.

Hotel & Lodging Reimbursement

Some warranties cover a certain amount of lodging if you can’t stay in the RV during the repair. This is where Wholesale Warranties is really taking care of RVers with their new Viking Protection contracts. You will be reimbursed for “trip interruption” expenses of: $150/day in hotel rooms (up to $750), $50/meal for 2 meals a day (up to $500), $75/day for a rental car (up to $450), up to $100 towards boarding your pet and up to $200 to cover a mobile mechanic’s upfront fee for coming out to your RV.

Towing and Roadside Assistance

Some warranty companies offer reimbursements for some amount of towing and/or roadside assistance. Wholesale Warranties‘ new Viking Protection reimburses up to $750 in towing expenses.

Canadian RVers and RVing in Canada

If you plan to travel to Canada, make sure the warranty company covers repairs done in Canada. Also, not all warranty companies cover RVs that are registered in Canada. Wholesale Warranties’ new Viking Protection does!


Final Notes

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We couldn’t be happier with our RV warranty so far, and have been convinced in the value of purchasing an RV warranty.

At this point we still have three years to go on our warranty, and we have a big repair looming as we tackle the problem with our fresh water tank. We have no idea how our RV warranty will come into play on that repair, or if it will at all, and of course, we will be posting and analyzing that repair!

It’s a pain to feel that you have to buy yet one more big ticket item for your RV, and I am the last person to say you need to do this or that in your RVing adventures. However, if you are interested, Wholesale Warranties is offering a $50 discount to our readers. Mention that you heard about them through our website, Roads Less Traveled, and they will deduct $50 from the quoted price at the time of purchase. Just be sure to ask! You can get a quote for your RV (not including the discount) at this link:

Wholesale Warranties Quote Form

Or you can call them at 800-939-2806. Ask for our contact, Missi Junior. Or email her at missi@wholesalewarranties.com.

NOTE: We had no idea during this first repair that in the next few months we would have a slew of major failures after our trailer axle was replaced. The summary of our warranty reimbursements to date is below:

Here's a summary of what our four year RV warranty through Wholesale Warranties cost, what our repairs WOULD HAVE cost, and what our warranty reimbursements have been to date:

Cost of Warranty $1,904
Total Cost of Repairs we've had done $7,834
Total Out of Pocket Costs for those repairs $1,145
Repair Reimbursements:
Trailer Axle Replacement $1,036
RV Refrigerator Replacement $1,647
Plumbing Issues & Window Leak $1,142
Suspension Replacement $2,550
RV Toilet Replacement $314
Total Repair Reimbursements $6,689

Our trailer warranty has paid for itself 3.5 times over!
Confused about the nitty gritty fine print buried in RV Extended Warranties? Here's an excellent detailed explanation!!

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RV / Marine Battery Charging – Solar & Shore Power Combined!

What happens when two RV or marine battery charging systems attempt to charge the batteries at the same time? The interactions between solar charge controllers, converters, inverter/chargers and engine alternators can be complex, and in our lives off the grid in a sailboat and RV, we have observed them working together in many different kinds of circumstances.

This page offers some insights into what goes on when two battery charging systems operate simultaneously, specifically: solar power and shore power, and solar power and an engine alternator. It is the fourth post in our series on RV and Marine Battery Charging Systems. The previous articles in this series are:

  1. RV and Marine Battery Charging Basics
  2. Converter, Inverter/Charger and Engine Alternator Battery Charging Systems
  3. Solar Charge Controllers – Optimizing Battery Charging from the Sun

This is a long post and you can navigate to the various sections using these links:



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When two battery charging systems are working side by side simultaneously, each follows its own internal algorithms to get the job done. However, when this happens, and the two charging systems measure the battery voltage to determine which charging stage they should each be in, they don’t see a “real” value. They see an artificially elevated battery voltage due to the presence of the other charging system. This can throw one or the other or both systems off of their normal Bulk-Absorb-Float cycle.

Because solar charging systems operate 24/7, the most common scenario in which two charging systems work simultaneously is solar charging and some form of artificially powered charging, either a converter or inverter/charger when the RV or boat is plugged into shore power or the generator is turned on, or an engine alternator when the boat or motorhome is under way.

The bottom line with two charging systems working simultaneously is that each will do a little work, but one will do more work than the other. Higher end solar charge controllers are designed to ensure that the batteries are never overcharged. As explained in the previous post about solar charge controllers, they are the gate keepers for the solar panels and will reduce the current coming in from the panels to 0 amps if need be.

There are many factors to consider when running an artificially powered charging system alongside a solar charging system. And in reality, just letting the two systems do their thing without worrying about how they get along is probably fine. But for those who want to ponder the relationships, here are some things we’ve learned.


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In order for all the charging systems on an RV or boat to work together truly harmoniously, it is helpful for the voltages at which the systems change charging stages to be the same across all the systems. For instance, each charging system should be set up with one common set of voltages similar to the following:

  • Bulk 14.7 volts
  • Absorb 14.7 volts
  • Float 13.5 volts

If these terms are confusing, have a peek at Battery Charging Basics.

Obviously, these voltages should be whatever values you have determined are optimal for your battery type. Unfortunately, some charging systems don’t allow you to enter specific voltages, so you may be stuck with whatever defaults the manufacturer chose or whatever “set” of voltages they provide that is closest to the values you want.

Flexible solar panels on a motorhome RV roof

Soaking up the sun:
600 watts of flexible solar panels we installed on a friend’s motorhome roof.

As you can see, if one system has an Absorb target voltage of 14.7 volts and another has an Absorb target voltage of 14.1 volts, there is going to be a conflict. What will happen is that the system that is aiming for the higher voltage will win out and raise the batteries to or towards the higher voltage. The reaction of the other system will depend on how it was designed to handle a situation where the battery voltage is higher than the stage it was in. This is true for all the target voltages (Bulk, Absorb and Float).

Similarly, all the charging systems on the RV or boat should be set up with the same algorithm for switching from one stage to the next. However, as shown in the posts about converters, inverter/chargers and engine Alternators and about solar charge controllers, this is not possible, because every product made by the many manufacturers who build these things has a unique charging algorithm.

There are some similarities, however. All multi-stage charging systems remain in the Bulk stage, pouring the maximum current they can into the batteries, until the Bulk voltage is reached. Then they switch to the Absorb stage. However, no two charging systems use the same criteria to exit the Absorb stage to go into Float. The Float stage is also handled differently by different chargers and manufacturers.



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Every RV and marine battery multi-stage charging system monitors the battery voltage to decide which stage to be in. How and where this voltage is measured and how each device is internally calibrated can make quite a difference.

For instance, the solar charge controller in a sailboat may be located as much as 20′ from the battery bank if the batteries are strung out from bow to stern in the bottom of the bilge and the charge controller is mounted in an aft compartment. Unless the charge controller is connected to the batteries with fairly beefy wires, there will be some voltage loss between the batteries and the charge controller, and the charge controller will get inaccurate readings of what the battery voltage actually is.

This can happen even if the distance is just 10′ but the wire used is too small for that distance. It can also happen if the engine alternator or the converter or the inverter/charger is a long distance from the batteries. Wire gauge sizes, distances and percentages of voltage lost are given in the following chart:

Wiring Gauge vs. Voltage Loss Chart


Higher end solar charge controllers are complex pieces of electronic engineering that are likely to be calibrated pretty well coming out of the factory. However, a cheapie single stage converter, like the factory installed units that come with so many RVs, may not be calibrated as well, and may be off in its measurement of the battery voltage by a tenth of a volt or more. Likewise with a simplistic engine alternator.

It was a big surprise to me to read in the user manual for our boat’s engine alternator/regulator (a Balmar ARS-4 multi-stage regulator) that the voltages may be off by +/- 3%. That means that a target Bulk voltage of 14.4 volts could vary between 14.0 volts and 14.8 volts. Hmmm. Not a lot of precision there!

Solar panels on a sailboat

Our solar panels catch some tropical rays on the back of our sailboat during our cruise in Mexico.

If the two charging systems that are working simultaneously are detecting different voltages on the batteries — for instance, the solar charge controller is measuring the batteries to be 14.5 volts while the converter is measuring them to be 14.7 volts — they will each react according to their own internal charging algorthims.

For instance, say both the solar charge controller and converter are in Bulk mode, trying to attain a voltage of 14.7 volts before switching to Absorb. When the batteries reach 14.7 volts according to the converter, the converter will think they have achieved the Bulk voltage already and will switch to the Absorb stage, while the solar charge controller will remain in the Bulk stage because it sees only 14.5 volts, and it will continue aiming for 14.7 volts, according to its internal measurements and algorithm.

What does this mean? It simply means that the solar charge controller will continue to let as much current in from the solar panels as they can produce while the converter will already be backing off how much current it puts into the batteries to hold them steady at what it perceives to be 14.7 volts (and which the solar charge controller sees as 14.5 volts). Not a big deal. The solar charge controller will keep pushing while the converter keeps backing off, and the job will eventually get done.



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The most challenging relationship we’ve had between charging systems was on our sailboat, and it was the one that forced me to investigate this whole business more deeply and to learn how to program a solar charge controller — and to discover, in the process, the value of programming one!

The two systems were our Balmar ARS-4 engine alternator/regulator and our Xantrex XW-MPPT-60-150 solar charge controller. The charging algorithms for these systems are described in detail here (for the alternator) and here (for the solar charger).

When I first observed them working together, I noticed two things right away.

1) Whenever we turned on the engine, the solar charge controller went into the Float stage soon afterwards.

2) Once the solar charge controller was in the Float stage, if we turned the engine off, it remained in the Float stage, even if the batteries hadn’t been fully charged by the engine alternator.

For instance, if the solar charge controller had been in the Absorb stage when we turned the engine on, and then we ran the engine for just 15 minutes and turned it off (not nearly long enough to charge the batteries), the solar charge controller would wind up in the Float stage and remain there for the rest of the day, depriving the batteries of a proper charge.

Engine Alternator Causes the Solar Charge Controller to Switch from Absorb to Float

The thing about batteries in a complex vehicle like a motorhome or a boat is that they are running many different systems that are continually turning on and off. In the case of our boat, when we were underway, any or all of our big systems might be in use at any one time: fridge and freezer compressors, radar, chartplotter, autopilot, anchor windlass, and even the microwave.

Marine diesel engine alternator Balmar ARS-4 100 amp

100 amp Balmar diesel engine alternator

Worst case, all of those things might be on at once for several minutes as we raised or lowered 200′ of stainless steel anchor chain with a 60 lb. anchor attached to the end of it (well, maybe not the microwave!).

Plus, there was no guarantee we’d run the engine long enough for the alternator to go through its Bulk and Absorb stages and charge the batteries completely.

We might run it for as little as a few minutes while moving from one anchoring spot to another, or for half an hour while we motored out of the bay to go daysailing.

We wouldn’t want to idle the engine at anchor just to charge the batteries, because the engine RPMs have to be fairly high for the alternator to generate a good charging current. These high RPMs happen naturally while driving the boat, but unfortunately, conventional wisdom says that revving the engine to high RPMs while not in gear (i.e., without a load on it) risks glazing the cylinder walls.

Besides it being random as to how long we might run the engine, it was also random as to what state the solar charge controller would be in when we started the engine up.

We might start the engine in the dark to raise the anchor, and in that case the solar charge controller would be asleep. Or we might do it early in the morning when the solar charge controller was in the Bulk stage and gamely trying to get whatever current it could from the wimpy sun on the horizon. Or we might do it later in the day when the solar charge controller was in the Absorb stage and cranking away.

We used a clamp-on ammeter to find out exactly what was going on at various points in the system. We put it around the alternator’s battery cable to see how much current the alternator was putting into the batteries. We also used it on the solar charge controller’s battery cable to verify that the current it displayed on its LCD screen was correct (it was).

Sperry Clamp-On Ammeter measures current from engine alternator

The alternator is pouring 77.9 amps into the batteries – WOW!!

Whenever we turned on the engine, regardless of what the solar charge controller was doing, the engine alternator would immediately go into the Bulk stage and dump as much current into the batteries as they needed to reach the alternator’s Bulk voltage.

If the solar charge controller had been in the Bulk stage already, its job would suddenly become much easier as it got a huge boost from the alternator.

If it had been putting 21 amps into the batteries and had been slowly raising the voltage towards 14.4 volts (the setting we had for the boat’s batteries), the engine alternator might contribute another 40 amps for a while, getting the batteries up to the Bulk voltage a whole lot faster than if the solar panels had continued working by themselves.

If the solar charge controller had been in the Absorb stage already, putting something like 18 amps into the batteries to hold the Absorb voltage of 14.4 volts, the engine alternator would begin its own Bulk stage regardless, and it would remain in the Bulk stage for 36 minutes as it followed its own internal algorithm.

The solar charge controller would react by backing off and delivering less current.

To make things more complicated, as these two systems worked through their charging stages, the loads on the batteries would be fluctuating widely as Mark and I went about our business of living on a boat.

If the fridge and freezer compressors were both running, and the autopilot was maintaining our course and the radar and chartplotter were on and we were making burritos in the microwave, the batteries would need a lot of current.

However, if neither compressor was on and someone was hand steering the boat, etc., then the batteries would need a whole lot less current. During those lulls in current demand, the solar charge controller would suddenly scale things way back and put just 8 or 9 amps from the panels into the batteries.

As soon as that happened, the solar charge controller would suddenly switch to the Float stage!


After some sleuthing, as described in the previous post, I realized that the charge controller was switching from Absorb to the Float stage because the current needed to maintain the Absorb voltage had dropped below 2% of the capacity of the battery bank.

2008 Hunter 44DS Sailboat Groovy in Tangolunda Bay Huatulco Mexico

In Tangolunda Bay (Huatulco, Mexico) we motored back and forth across the bay every few days to anchor out of the swell as it changed its flow.

Since I had entered the true value of the battery bank (710 amp-hours), the controller switched from Absorb to Float when the current dropped below 14 amps (2% of 710).

So, I lied to the controller and told it the battery bank was just 250 amp-hours. Then it would remain in Absorb down to 5 amps.

What I found (by trial and error) was that the solar charge controller pretty much always needed more than 5 amps when it was in Bulk or Absorb.

I don’t know why the alternator didn’t produce that last 5 or so amps on its own, but I suspect it was because the alternator’s Absorb voltage was set to 14.2 volts while the solar charge controller’s Absorb voltage was set to 14.4 volts (the alternator had “sets” of values for the three target voltages, and 14.2 volts for Absorb was in what I felt at the time was the most appropriate set).

The Solar Charge Controller Gets Stuck in the Float Stage

The second problem I encountered was that in the event that the solar charge controller went into the Float stage prematurely, then, after the engine was turned off it would remain there until the next morning.

Xantrex XW MPPT 60-150 Solar Charge Controller

Xantrex solar charge controller
(bottom plate removed)

Yet the batteries may not have been fully charged by the alternator, and they may have really needed to remain in Absorb with the solar panels charging them at a fast clip for another hour or two.

In this case, the solar charge controller needed either to resume the Absorb stage or cycle back through the Bulk stage as soon as the engine was turned off.

The only way the Xantrex XW MPPT 60-150 would cycle back through the Bulk stage is if the battery voltage dropped below a certain level.

I experimented with different voltages. The Float voltage was 13.4 volts, so if I set the “ReBulk” voltage to be 13.5 volts or higher, then the charge controller would never get into the Float stage at all, because it would keep cycling back to Bulk.

According to the user manual, this is actually a valid way to operate this solar charge controller, and they even provide a programming parameter that sets the charge controller up to be a “two stage” charger that has no Float stage and has just the Bulk and Absorb stages.

I wasn’t comfortable with not having a Float stage (although in hindsight that probably would have been just fine given the intermittent heavy loads that were on the batteries all day long). In the end, I settled on a ReBulk value of 12.9 volts.

So, if the solar charge controller was in the Float stage after the engine was turned off, and a big load came on some time afterwards that drew the battery voltage down from 13.4 volts to below 12.9 volts (microwave plus fridge and freezer, for instance), then the solar charge controller would cycle back through the Bulk stage and start the charging cycle all over again.

Programming For Storage

Periodically, we left the boat for a month or several months at a time when we traveled inland or went back to our RV for hurricane season. Since the fridge and freezer would be turned off, and there would be no loads on the batteries at all, I would undo these two programming changes. I would reprogram the solar charge controller with the true size of the battery bank so it would switch from Absorb to Float at 14 amps rather than 5, and I would change the “ReBulk” voltage back to 12.5, the factory default.



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Sometimes There Are Good Reasons Not To Plug In!

Solar power is free, however, the electricity from shore power hookups may not be. If your shore power electricity is “free” (i.e., built into the overnight fee you are paying for your RV site or boat slip), then it doesn’t really matter which charging system is dominant.

If you have metered electricity (a common situation if you are renting your RV site or your boat slip on a monthly, seasonal or annual basis), and you are paying for your electricity, then you may want to ensure that your solar charger is running the show and doing the bulk of the work while your converter or inverter/charger is playing second fiddle.

One easy way to do this is just to flip off the electric switch on the shore power post. Flip it on only as needed when the batteries get low and need a boost.

We did this a lot when we lived on our sailboat. We lived at a slip in Paradise Village Marina in Puerto Vallarta, Mexico, as well as at slips at Hotel Coral and at Cruiseport Marina in Ensenada Mexico for months at a time without plugging in the shore power cord at all. During hurricane seasons, we also left our boat in a slip in Marina Chiapas for seven months without plugging it into shore power.

It was nice when we settled up the bills for these places at the end of each stay to have a big ol’ “$0” on the line item for electricity.

What Happens If You DO Plug In?

If your RV or boat is plugged into shore power, and the switch at the post is turned on, it is hard to get the solar power system to be dominant because its power source is flakey (as explained here).

We plugged our sailboat into shore power for several months while we lived aboard at Kona Kai Marina in San Diego at the end of our cruise.

Schneider Electric 2500 watt inverter charger Xantrex

Schneider Electric (Xantrex)
2500 watt Freedom inverter / charger

Our Xantrex inverter/charger went through the Bulk and Absorb stages the first time we plugged in, and then it remained in the Float stage forever after (except when we unplugged to go day sailing and plugged back in again upon returning)!

Each morning when our Xantrex solar charge controller woke up, it zipped through the charging stages and went into the Float stage after just a few minutes, because it saw the batteries were already fully charged.

In our RV, we plugged into shore power for 48 hours during rainy and stormy skies while we stayed at Narrows Too RV Resort in Maine. It was overcast when we plugged in. Our Outback solar charge controller was in the Bulk stage putting about 6 amps into the batteries at around 13.9 volts (it was aiming for 14.7 volts).

Ordinarily, since we live a solar power only lifestyle, our Outback solar charger is set up with Bulk and Absorb values of 14.7 volts, a minimum Absorb time of 2 hours and a maximum Absorb time of 4 hours. However, our Iota DLS-90 / IQ4 Converter has a fixed (non-modifiable) Bulk voltage of 14.6 volts and Absorb voltage of 14.2 volts and Absorb time of 8 hours.

I temporarily changed the solar charge controller to have Bulk and Absorb voltages that matched the converter, and minimum and maximum Absorb times of 0 hours so it would remain in Absorb only as long as it took to get to Bulk (the charging algorithm of the Outback solar charge controller is explained in detail here).

Iota DLS 90 IQ4 Converter and smart charger

Iota DLS 90 IQ4 Converter and smart charger ready for installation in our RV

As soon as we plugged in, the converter began dumping 49 amps into the batteries which zoomed the battery voltage up to the converter’s Bulk stage value of 14.6 volts. Then it backed way off to 30 amps, then 20, then 15 as it held the converter’s and solar charger’s Absorb voltage of 14.2 volts (our new Trojan Reliant AGM 6 volt batteries charge up extraordinarily quickly!).

The Outback solar charge controller responded by putting in a few amps at first, but then it displayed “Bat Full” and went to sleep!

From there, the Outback solar charge controller went through its usual Sleeping and ZZZZ stages as the Iota DLS-90 / IQ4 Converter quietly slipped from Absorb (14.2 volts) to Float (13.6 volts). When the Outback solar charge controller went through its wakeup sequence after being in the ZZZZ stage for 3 hours, it saw the batteries were fully charged, so it rolled over and went back to sleep in the ZZZZ mode.

Outback FlexMax 60 Solar Charge Controller

We catch our RV’s solar charge controller sleeping on the job at midday!
The solar panels are in full sun and are at 68 volts
The converter is in control and has elevated the batteries to 13.5v
But the controller sleeps soundly as 0 amps go from the panels to the batteries!

In fact, the whole rest of the time we were plugged into shore power, the Outback solar charger stayed in the ZZZZ mode, even in bright afternoon sunshine. Every 3 hours it would lazily open its eyes, yawn, look at the state of the batteries, see that they were fully charged and go right back to dreamland in the ZZZZ mode.

To summarize, these are two examples of how different solar charge controllers handled the presence of full-time shore power:

Do The Different Charging Voltages Have To Match?

No. On another occasion, while getting repairs done at an RV dealership, we plugged in our trailer for an afternoon while it was out on the lot next to the building on a cloudy day. The solar charge controller was putting in 6 amps at 13.8 volts in the Absorb stage (trying to keep the batteries at 14.7 volts) at mid-afternoon.

As soon as the shore power cord was plugged in, the converter began dumping 55 amps into the batteries and the battery voltage zoomed to 14.6 volts. The solar charge controller kept putting in around 6 amps.

For the next few minutes, the total current going into the batteries dropped from 61 amps to 33 amps and then settled there. If the solar charge controller could put in 8 amps, as the sky lightened, the converter put in 25 amps. If the solar charge controller could put in only 2 amps as the sky darkened, the converter put in 31 amps.

Suddenly, the converter switched to its Absorb stage where it holds the batteries at 14.2 volts, and the total current going into the batteries dropped to 20 amps. The solar charge controller was still in its own Absorb stage where it wanted to hold the batteries at 14.7 volts, so it kept putting in as much current as it could (5 to 8 amps and even as high as 12 when the sun came out for a few minutes) while the converter made up the difference, keeping the total at around 20 amps.

We didn’t stay plugged in long enough to see the solar charge controller switch to Float (the converter stays in Absorb for 8 hours), but at that point the converter would have held the batteries at 14.2 volts while the solar charge controller wanted them at 13.5 volts. It also would have been dark, so the converter would have been in complete control and the solar charge controller would have gone to sleep.



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If you are using a generator to give the batteries a boost of charge because you’ve been in cloudy conditions or don’t have enough solar power to run everything on board indefinitely, then you’ll want the generator to charge the batteries as quickly as possible, saving you a few dollars in fuel (gas or diesel) and saving yourself from the loud noise and obnoxious fumes of the generator itself.

Yamaha 2400i Portable Gas Generator

Yamaha 2400i generator — our backup

In essence, the goal with a generator is to run it for as short a time as possible to get the batteries charged up.

With solar power, at the end of the day, before nightfall, the batteries are in their most charged state.

During the evening and into the darkest hours of the night, the batteries get depleted from running the lights, the TV, the computers, the microwave and whatever else your household uses until bedtime.

By dawn, the batteries are at their lowest state of charge. This is also a time when the sun is low in the sky and the solar panels are operating weakly and producing minimal current.

Early morning is the ideal time to turn on the generator!

An Example of Generator Use at Midday versus Dawn

The first time we fired up our generator to charge our batteries via the Iota DLS-90 / IQ4 converter, we’d had several overcast days in a row. It was mid-afternoon, and the batteries were fairly depleted from days of cloudiness. However, they had already gotten about 25 amp-hours of charge during the morning and noon hour, so they weren’t as depleted as they had been at dawn.

The solar panels were limping along in the Bulk stage with the batteries at about 13.5 volts. The solar charge controller was aiming at a Bulk voltage of 14.7 volts and the panels were valiantly trying to produce enough current to get there, but all they could muster was about 6 amps. It wasn’t likely the batteries would reach the Float stage before dark.

As soon as we turned on the generator, the the Iota converter went into the Bulk stage and began delivering about 60 amps to the batteries. It quickly got them up to 14.6 volts and switched to Absorb, dropping to about 20 amps. Great! But this converter is capable of putting 90 amps into the batteries, so why run it when Bulk mode delivers just 20 amps?

Solar panels on a fifth wheel RV roof

We let the solar panels do their job during the day.

We decided turn off the generator and let the solar panels do whatever they could for the rest of the day.

Early the next morning when the batteries were depleted from several days of inadequate charging plus a night of activity in the RV (they were down to about 12.3 volts), we fired it up again.

I did not modify the settings on the Outback solar charge controller to match those of the converter because we were just going to run the generator for a few hours and probably wouldn’t need it again for a few months.

This time the converter rolled up its sleeves and got to work, pumping 67 amps into the batteries as it aimed for its target Bulk voltage of 14.6 volts. The solar charge controller was in Bulk mode too and was busy putting in 1-2 amps of its own (it was early morning), and with the converter’s assistance, it briefly hit 14.7 volt Bulk target and switched to Absorb.

With both the converter and solar charge controller operating in the Absorb stage, the converter dropped the current to maintain the target Absorb voltage. The solar charge controller could still bring only 1-2 amps to the party due to the low light, so the converter was in control and doing virtually all the work.

We shut off the generator off after about two hours and let the solar charge controller take over. Now that the batteries were partially charged up, the solar charge controller was able to get the batteries up to its Absorb voltage target and finish the job, even in the overcast conditions, getting the batteries through its Absorb stage and going into the Float stage for the first time in a few days.




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So, you can see, there are many ways to charge RV and boat batteries and many things to consider. Of course, it’s easy enough to leave the various charging systems at their factory settings after installing them, and there is nothing wrong with that!

But if you want to understand your system and get the most out of it — especially if you are using solar power and end up running a second charging system in conjunction with your solar power system — you may want to dig into the nitty gritty details buried in the user manuals and figure out what the charging algorithms are and how to program each system with the parameters that make the most sense for you.

All battery charging systems for mobile installations like RVs and boats have become increasingly more sophisticated over the years. A quick review of the older systems described in detail in the previous posts here and here show how the engineers designing these systems have become more and more knowledgeable about the real world applications of their products and what conditions they might encounter as they interact with other charging systems.

As the years go by from here forward, more and more solar charge controllers, inverter/chargers, converters and engine alternators will be designed with the understanding that they may not be the only charging system operating in the RV or boat.

This was the last article in our series on RV and Marine Battery Charging:

Related posts about batteries, solar power and living off the grid in an RV or boat:

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Solar Charge Controllers – Optimizing RV Battery Charging

The solar charge controller is the heart of any solar power installation on an RV or boat. It is the gatekeeper between the solar panels and the batteries, and it determines how much of the sun’s energy that is available to the solar panels will actually be converted into electrical current to charge the batteries.

Because solar power is a “set it and forget it” type of system, it is not “mission critical” to understand the inner workings of these complex pieces of gear. However, if you want to get the most out of your solar panels, you may want to fine tune your system to increase its battery charging capacity by programming the solar charge controller for optimal performance.

This page gives the low-down on how solar charge controllers work, presents ideas for how to size them, and explains what the typical input parameters are and how they affect performance. It then explores three specific charge controllers made by three different manufacturers, and compares the unique ways that each manufacturer has tackled the challenge of multi-stage charging via the sun.

Since we started traveling full-time in 2007, as of June 2019, we have used, worked with and lived with these particular units for over 4,000 nights of living off the grid in our RV and sailboat.

1200 Solar Charge Controllers and RV Battery Charging

An in depth look at solar charge controllers

This is the third part of our 4-part series on RV and marine battery charging systems.

So far in this series, we have reviewed the basic concepts involved in charging RV and marine batteries, including an in-depth review of multi-stage charging, and we also have looked at how “artificially powered” charging systems like converters, inverter/chargers and engine alternators go about the process of battery charging. The other parts in this series are:

This is a long post and you can read it in stages and navigate to the different sections by clicking on the links below:



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Solar charge controllers are a lot more complex than all of the charging systems described so far in this series (converters, inverter/chargers and engine alternators), and they offer a lot more flexibility for programming too, usually through a menu driven screen interface. What makes these systems so complicated?

— The sun not a consistent power source like the local power plant or an engine

“Artificially powered” chargers like converters, inverter/chargers and engine alternators have unlimited power backing them, either from electricity at a power plant or an engine. This allows them to perform optimally no matter what the circumstances are. In contrast, solar charge controllers are dealing with a very flaky power source.

The sun — flaky? Yes! The energy available from the sun varies all day long. At noon when the sun is high in the sky there’s a lot more energy available than in the morning and evening when it is low. The sun also gets covered by clouds now and then, and sometimes it goes away all together or never comes out all day.

Storm clouds swirl above our RV

The solar panels COULD be working, but…

In summertime, the days are long and the sun is out for many hours. In winter, the days are short and the sun is out very little (if at all — think Alaska). And every night all year long the sun vanishes for hours. Trees and buildings can cast shadows on solar panels, affecting their ability to generate current. For boats at anchor, sometimes the mast or boom will shade the solar panels every few minutes as the boat swings back and forth, making the current coming in from the panels rise and fall repeatedly.

— Solar panels can’t always do the job at hand

The batteries on an RV or boat are charged by the sun as long as it is light, regardless of what kinds of electrical appliances you are running inside. Sometimes there’s enough extra energy from the sun that the panels can do two jobs: charge the batteries AND support things like hair dryers and microwaves. But at certain times of the day, the solar panels may not be able to produce enough current to power those appliances AND charge the batteries at the same time by holding them at their target Absorb or Float voltage.

Solar power is difficult when cloudy

The solar charge controller keeps busy as the sun comes and goes

The net effect may be that the batteries are actually be being discharged while those loads are running, even though the solar panels are actively charging them. Sure, the sun mitigates the discharge rate, but overall the batteries are giving up more current than they are receiving from the solar panels. This temporary period of discharging means the solar charge controller will need to keep the batteries in the charging state a little longer to make up for the lost charging time.

— Solar charge controllers operate 24/7

Another difference between artificially powered and naturally powered charging systems is that solar charge controllers do not get turned on and off or plugged in and unplugged. Solar charge controllers operate 24/7, and they are busy communicating with the solar panels all the time to see how the sun is affecting them. At night, solar charge controllers stop talking to the panels quite so frequently since they know the sun won’t shine again for many hours. They “sleep” for a few hours, waking up periodically to see if the sun has risen yet.

Because there is no on/off switch, there isn’t necessarily an easy way for a solar charge controller to be forced into Bulk mode other than by virtue of the “wake-up” phase first thing in the morning. If, for instance, you want to force a solar charge controller into the Bulk stage at 2:00 in the afternoon, you may or may not be able to, depending on the unit.

— No two solar charge controllers are alike

Each solar charge controller manufacturer has a different way of dealing with the inconsistencies of solar power production. Some are easy to program and some are more difficult. Some have many adjustable input parameters and some have just a few. Some can be forced to start a Bulk charge at any time, and some can’t.




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Generally, a solar charge controller wakes up and immediately puts the batteries in the Bulk stage. Sounds great! However, the Bulk stage in low light may mean the batteries are getting just a trickle charge of an amp or two, because the solar panels can’t produce any more than that.

This means that frequently, for much of the morning, even though the solar charge controller is in Bulk and you’d expect the batteries to be getting blasted with current (which would be happening with an “artificially powered” charging system), the batteries are actually getting just a few anemic amps while the sun is slowly rising in the sky.

Depending on their state of charge at dawn and the size of the solar panel array, this trickle charge might actually be enough for the batteries to reach the Bulk voltage sometime before lunch. They will then switch out of the Bulk stage and into the Absorb stage before the sun has actually reached its peak in the sky where it can produce max energy.

Isn’t it ironic that by the time the solar panels are able to operate at full power, the batteries may not need it any more?!

However, having the batteries out of Bulk and into the Absorb stage during the hours that the sun is highest in the sky is actually optimal. The current delivered by the solar charge controller can slowly taper off as the sun falls lower during the afternoon. Once the Absorb stage is done, and the solar charge controller is operating in the Float stage, the low angle of the sun and the panels’ reduced ability to produce current is not a problem because the charge controller now wants to deliver less to the batteries anyway.

All this is great for sunny days… but not everyday is sunny!

On the other hand, it may be a cloudy morning until noon, or the RV may be in the shade of a mountain until noon, so by the time lunch rolls around, the batteries are still just as discharged as they were at breakfast — or even more discharged because you spent the morning playing on the computer or watching TV.

Lots of solar panels

Lots of solar panels

Now, when the sun comes out or the mountain’s shadow moves off the RV’s panels, the solar charge controller is still in Bulk mode. Suddenly the panels can run full blast and operate as close to their rated output current as possible (how close they can operate to their rated maximum depends on how close they are to being perfectly perpendicular to the sun’s rays).

In this case, having a bigger solar panel array is helpful because now it becomes a race with the clock to get the batteries through the Bulk stage and through the Absorb stage before the sun gets too low in the sky in the late afternoon.

And of course there are those cloudy days, or rainy days, and/or short winter days, when, try as they might, the solar panels just can’t produce the current needed to get the batteries through the Bulk and Absorb stages completely by the end of the day. On these days, you hope for more sun the next day or, if you get a bunch of these days in a row, eventually you turn to an artificially powered charging system like a converter or a inverter/charger ((via a portable gas generator or an onboard generator or shore power electricicity) or an engine alternator to finish the job.




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The rule of thumb for sizing solar charge controllers is not the same as for sizing artificially powered chargers. Remember, in Part 1 of this series, we mentioned there is a rule of thumb that says a battery charging system’s max output current should be roughly 25% of the capacity of the battery bank. This means that, in very approximate terms, a 440 amp-hour battery bank needs a 110 amp charging system.

However, solar charge controllers are generally sized to a solar panel array rather than to a battery bank. The sizing parameters for a solar charge controller are the maximum number of watts coming in from the solar panel array and the maximum current going out to the batteries. Add up the total watts in the solar panel array and the maximum amount of current the array can produce, and make sure those numbers are within the specs of the solar charge controller.

The traditional rule of thumb for sizing a solar panel array to a battery bank is that the total watts should be more or less equivalent to the amp-hour capacity of the battery bank.

Conventional Rule of Thumb:

Total solar panel array watts = Total battery amp-hours

However, this may end up under-sizing the solar panel array just a bit. As an alternative, you might start by sizing the solar charge controller to the battery bank using the 25% rule of thumb for sizing battery chargers to batteries:

1 – Solar charge controller output current = 25% Total battery amp-hours

THEN size the solar panel array so it maxes out the total watts and total open circuit voltage specified for the solar charge controller.

2 – Total solar panel array watts = Maximum input watts for Solar charge controller

Here’s an example using a 435 amp-hour battery bank of four Trojan T-105 Reliant AGM golf cart style batteries as a starting point. This is our battery bank and is the maximum amount of battery capacity our 36′ fifth wheel trailer can carry comfortably due to weight and space constraints.

Using the Conventional Rule of Thumb above, the total wattage of the solar panel array would be approximately 450 watts. This is sufficient in the summer months in North America and might be sufficient at the equator or in the Land of the Midnight Sun in the winter months, but in our experience, our 490 watts of solar panels on our RV roof is inadequate during winters in the southern US when the sun is low in the sky, the days are short and winter storms create overcast skies for days on end.

Using the Two Step sizing method above instead, you would choose a solar charge controller that has a maximum current output of 25% of 435 amps = ~108 amps. The Outback FlexMax 80 is an 80 amp solar charger (relatively close to the 108 we’re looking for). It can support up to 1,000 watts of 12 volt solar panels (and more watts for higher voltage panels). Note that to get 80 amps of current, you’d need to have the solar panels facing 90 degrees to the sun, and the solar charge controller would need to be operating in the Bulk stage.

Sizing the solar charge controller this way, we are now looking at 1,000 watts of solar panels instead of the 450 watts that the Conventional Rule of Thumb came up with — twice as much!

This sizing method is probably overkill. However, it might make sense to size the panels and controller both ways and choose something in between. As I’ve said, in our case, 600 to 800 watts lying flat on our RV roof without tilting would be nice in winter.

Boat solar power installation

Our sailboat had 555 watts of solar power.
Note the shade on the panels from the mast and spreaders.

For us, on our boat (710 amp-hour battery bank) we could have used a 750 watt to 1,000 watt solar panel array instead of the 555 watts we had to run the systems we had on board, despite having ample sunshine throughout our cruise.

All of this is given here as food for thought. Sizing panels and batteries and solar charge controllers is all very flexible. More of everything is better, but the reality is that there are roof space constraints for the panels, and there are both weight and space constraints for the batteries, and those limitations will ultimately dictate your particular options for panels and batteries.

A truck camper and a Class A diesel pusher (or a Catalina 27 sailboat and a Nordhavn 62 trawler) obviously have different constraints and needs.

In very general terms, anything from a 450 amp-hour / 500 watt system to a 900 amp-hour / 1,200 watt system is fine for both boats and RVs that are used to boondock or anchor out for months on end, depending on whether you run electric refrigeration and how much you stay up at night watching TV with the lights on and/or stay home during the day using computers, electric appliances and power tools.




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Now that we’ve seen the challenges that solar charge controllers face, let’s look at a specific example.

We installed an Outback MX60 MPPT solar charge controller in our fifth wheel trailer. It’s been in operation all day everyday that we’ve been in our trailer since we purchased it new in 2008. Since then, the Outback MX60 model has been discontinued and replaced by the new and improved Outback FlexMax 60 solar charge Controller.

The Outback FlexMax 60 MPPT Solar Charge Controller has the following algorithm:

BULK: Deliver maximum current until the Bulk voltage is reached.

ABSORB: Deliver as much current as necessary for the batteries to maintain the Absorb voltage. Transition to the Float stage when one of the following things happens:

  • The charger has been in the Absorb stage for as long as it took for the batteries to reach the Bulk voltage.
  • The current coming from the batteries has dropped below a certain level

If the sun fades and the controller can’t deliver enough current to keep the batteries at the Absorb voltage, extend how long the batteries stay in Absorb by the length of time the voltage fell below the Absorb voltage.

FLOAT: Deliver enough current to keep the batteries at the Float voltage.

EQUALIZE: Equalization voltage and time parameters are programmable, and equalizing can be done automatically or started manual. If Equalizing can’t be completed in one day, the batteries will resume equalizing the next day until the equalizing time has been completed.

Everything in the Outback MX60 charge controller (and the Outback FlexMax 60/80 Solar Charge Controllers) is programmable on a four-line LED menu driven display. You enter the battery type (Flooded, Gel, AGM) and that gives you default values for Bulk, Absorb and Float voltages. You can then override those values with values of your own if you wish.

So, how does this solar charge controller compare to a converter, inverter/charger or engine alternator?

If you compare the Outback MX60’s charging algorithm shown above to that of any of the artificially powered charge controllers described in the previous article, you can see just how very much more complicated this solar charge controller is. Here’s a little more detail:



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The key part of any multi-stage charging algorithm is when to switch from the Absorb stage to the Float stage. (If you are unclear about those stages, read more here: RV and Maring Battery Charging Basics). All charging systems use TIME as a basic criteria. The question is how long?? Should the batteries stay in Absorb for 2 hours or 4 hours? Should it always be the same amount of time?

To be most amenable to the batteries’ needs, the state of charge of the batteries when they first start charging must be taken into account. If the batteries are nearly fully charged when charging starts, why keep them in Absorb for three hours? That’s like forcing down extra helpings of pie after a big Thanksgiving dinner. Maybe just a small piece is enough on a full stomach.

On the other hand, if the batteries are deeply discharged when the charging begins, they should stay in Absorb longer to make sure they really get full. If you didn’t nibble on hors d’oeuvres before dinner and you skipped lunch and breakfast, then extras helpings of everything at the Thanksgiving table might taste and feel great.

Outback tackles this conundrum by looking at how long it takes the batteries to reach the Bulk voltage. If they are well charged already, they’ll zip to the Bulk voltage quickly. In that case, they don’t need to stay in the Absorb stage for very long. On the other hand, if they are deeply discharged, it will take a long time for them to reach the Bulk voltage. In that case, they should hang out in Absorb for a long time until they are really and truly fully charged.

The way the Outback charge controllers accomplish this flexibility in the length of time of the Absorb stage is that they make the Absorb stage last for the same length of time as the Bulk stage did. If Bulk took 2 hours, then Absorb will last for 2 hours. If Bulk took 3 hours, Absorb will be 3 hours. Clever!



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Unfortunately, the sun isn’t all that consistent for such a basic algorithm, and there is more to it than just a simple one-to-one relationship between Bulk and Absorb. What makes this business tricky is that the sun may not allow the charger to hold the batteries at the Absorb target voltage once they begin Absorbing. For instance, in the middle of the Absorb stage, the sky might cloud over. The charge controller will respond by instantly opening the floodgates for the batteries so it can get the necessary current from the panels to keep the batteries at the Absorb voltage. But if the panels can’t deliver, there’s nothing the solar charge controller can do, and the battery voltage will fall below the Absorb voltage.

Outback FlexMax 60 MPPT Solar Charge Controller

Outback FlexMax 60 MPPT Solar Charge Controller

In another scenario, someone in the RV or boat might turn on an electrical appliance that draws a lot of current — more than the panels can deliver — and this will temporarily lower the battery voltage below the target voltage. Running the vacuum or a hair dryer in addition to whatever else is running in the RV or boat might be just enough to draw more current from the batteries than the sun on the panels can produce.

In these cases, the solar charge controller will try to keep the batteries in the Absorb stage, but it’s failing. The thing is, if there isn’t enough current to keep the batteries at the Absorb voltage, are they really Absorbing? Not exactly. They’re getting as much current as possible, but the voltage has dropped below the Absorb stage threshold.

The Outback charge controllers view this as a kind of “timeout” period. So, for every minute of this “timeout,” they tack on a minute of extra time that the batteries must stay in Absorb before they switch to float.

For instance, if the batteries have been in Absorb for 53 minutes when the sky suddenly clouds over, the Outback charge controller will start counting how long the batteries stay below the Absorb voltage. If they stay below for 14 minutes, then once the sun comes back out and they get back to the Absorb voltage, they will need to stay in Absorb for an extra 14 minutes on top of the time period they were planning on (which is either the length of time that the Bulk stage took that day or a minimum amount of time programmed by the user). When they resume Absorbing, the Outback will resume counting from 53 minutes with a new target time that is 14 minutes longer than before.

This problem of the solar panels not being able to deliver enough current to keep the batteries at the target voltage exists in the Float stage as well as the Absorb stage. However, in the case of the Float stage there is no time consideration. Once they get into Float, the batteries will stay there (or attempt to stay there) until dark.

If you are confused, here is a real live example:

One day around noon our batteries had reached the Float stage (we’d gone to bed early the night before, so the batteries had charged up quickly). They were humming along getting about 4 to 10 amps or so to maintain a 13.5 Float Voltage with whatever stuff we had running in the RV (laptops, etc.).

I got out the vacuum, and when I turned it on, the charge controller jumped into high gear, demanding max output from the solar panels. The panels could deliver 25.6 amps, but that wasn’t enough to maintain the Float voltage of 13.6, and the battery voltage dropped to 13.1 until I finished vacuuming. Then everything went back to where it had been.

Lesson learned: use a broom not a vacuum!

You can see the display from the Outback charge controller here:

Outback MX60 Solar Charge Controller

Outback MX60 Charge Controller display at midday with vacuum & computers running.
Note the batteries have dropped to 13.1 volts (below Float) and the current coming from the panels to the batteries is a huge (for “Float”) 25.6 amps to support the load in the RV. “F-MPPT” means “I’m in the Float Stage but I need max power ’cause I can’t maintain the Float Voltage.”

Even if the sun is out all day long and the batteries reach the Float stage, at the end of the day when the sun begins to set, the charger will no longer be able to hold the Float voltage. As it gets darker and darker, the charger will try valiantly to hold the Float voltage, but the battery voltage will drop lower and lower while the charge controller delivers less and less current.

Eventually, when it gets completely dark outside, no current will be going to the batteries at all. If the batteries were in Float before the sun went down, they will settle out at 12.7 volts, fully charged. If they never reached the Float stage, however, you’ve gotta cross your fingers for good sunshine tomorrow!




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As I mentioned in the previous article in the description of the Xantrex Freedom 25 Inverter/Charger, a rule of thumb is to switch from Absorb to Float when the current that the batteries need to remain at the Absorb voltage drops below 2% of the amp-hour capacity of the battery bank.

For a 450 amp-hour battery bank, this would be 9 amps. For a 750 amp-hour battery bank, this would be 15 amps. So, for a 450 amp-hour battery bank, a reasonable time to switch from Absorb to Float is when the current drops below 9 amps. For a 750 amp-hour battery bank it is when the current drops below 15 amps.

The Outback FlexMax 60 (and 80) allow you to enter whatever number of amps seems right to you, whether it is 2% of your battery bank or some other number that you prefer.

Why is it important to switch from Absorb to Float when the amount of current the batteries need to remain at the Absorb voltage drops below a certain level?

The batteries may be nearly fully charged, but if the charging algorithm forces them to stay in Absorb for a set period of time — three hours for instance — they may need just 1 or 2 amps to maintain the Absorb voltage. It might be better for the batteries if they were allowed to slip back to the Float voltage at that point rather than forcing them to stay at 14.7 volts while accepting a minuscule amount of current until the 3 hours is up.

However, the reverse may also be true. There may be situations where you don’t want the batteries to be in the Float stage even though the charging current has dropped below 2% of the battery bank capacity. More on that further down.



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Because solar charge controllers operate 24/7, there are three more states that the Outbacks can be in:

  • SNOOZING: The voltage of the solar panels is greater than the voltage of the batteries but there is no current coming in from them
  • SLEEPING: The voltage of the solar panel array is less than the voltage of the batteries
  • ZZZZZ…: The solar charge controller has been in the SLEEPING state for 3 hours or more

The controller has an algorithm for waking up as well. As the sun rises, once the voltage of the solar panels is more than 2 volts higher than the voltage of the batteries (i.e., the panels are at 14.7 volts or more if the batteries are fully charged at 12.7 volts), it looks for current coming in from the panels. If the current is still near 0, it SNOOZES in 5 minute intervals while it waits for the current to reach about an amp. Then it goes into Bulk and starts its work for the day. This happens each morning as the sky becomes light and the solar panel voltage rises from 0.



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It doesn’t take much light to bring a 400+ watt 12 volt solar panel array up to 15 volts. A full moon with clear skies may raise the voltage on the panels to this level, and parking under a bright street light will definitely do it. This is not enough light for the solar panels to generate current, but it can sometimes be enough to fool the charge controller that the sun might be about to rise and give it a sleepless night.

We have seen our solar charge controller pull an all-nighter as it alternated between SNOOZING and WAKE-UP all night long because the solar panel array was steady at 15 volts from a street light overhead while the batteries were at 12.7 volts.

The charge controller couldn’t start the real SLEEPING phase because the panel voltage was higher than the battery voltage. But there wasn’t enough light to generate any current either. So, the controller would WAKE-UP, discover there was no current coming in from the panels, and then it would go back to bed and SNOOZE a little longer. It would repeat this unfortunate cycle all night long, never getting into the really good 3 hour long ZZZZ… sleep stage (poor thing!).

On the other hand, while staying in the Catskill Mountains about 120 miles from New York City, I crept out at 2:00 in the morning to see how the charge controller was doing. The city lights kept the sky from being very dark, and the panel voltage was elevated slightly to 9 volts rather than the usual 0 volts we see in more rural areas. However, the batteries were more than 2 volts higher than that at 12.7, so the charge controller was well into its REM sleep phase, dreaming of sunny days. (Mark crept out to photograph the fireflies…a much better reason to climb out of bed at 2 am!!)

Outback FlexMax solar charge controller sleeping near NYC

At 2:00 a.m. in the Catskills, the lights of NYC reflecting off low clouds raise the Panel Voltage to 9 volts. The previous day the batteries got 73 amp-hours of charge, so they are fully charged at 12.7 volts, more than 2 volts higher than the panels. The controller is sleeping soundly for 3 hours when it will check the panel voltage again.



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We installed a Xantrex XW MPPT 60-150 Solar Charge Controller on our sailboat. Xantrex is now Schneider Electric, and this unit has been replaced with the Schneider Electric XW MPPT 60-150 solar charge controller. I don’t know if this is just a name change on the unit or if the design of the unit has changed in any way.

This solar charge controller is about the same size as the Outback but has a two line LCD display instead of four, so you have to scroll through the menus a bit to get the same info you can see at a glance on the Outback.

The challenge for us on our boat was that we had a smaller solar panel array than we needed for our typical daily power consumption due to our electric (DC) fridge and standalone freezer. 555 watts of solar power was not enough. So, we needed the charge controller to get the solar panels to provide as much current as possible everyday.

Unfortunately, it took us a while to realize that the factory default settings on the Xantrex charge controller were preventing the solar panels from providing as much current as they could.

The Xantrex charge controller came with a factory default setting to switch from Absorb to Float when the current being delivered to the batteries dropped below 2% of the amp-hour capacity of the battery bank, or 14 amps.

Xantrex XW MPPT 60-150 Solar Charge Controller in a sailboat

Our Xantrex XW MPPT60-150 charge controller on our sailboat

The problem was that once the current going to the batteries dropped below 14 amps, the solar charge controller put them into the Float stage. In the Float stage they needed much less current to maintain the Float voltage, usually around 5 amps. That’s a lot less than the nearly 14 amps they had been getting in Absorb!

What this meant was that even if the sun was shining brightly, the batteries were being given less current than the panels were capable of delivering because the solar charge controller had put them in the Float stage. The gatekeeper had closed the gate most of the way!

We would watch the system go into the Float stage at 1:00 p.m. and waste the best sunshine of the day sitting in the Float stage all afternoon charging the batteries with a lot less current than it would have if the controller were still in Absorb.

So, because the Xantrex charge controller had the programming option available, we programmed it to switch into Float when the batteries needed only 5 amps to maintain the Absorb voltage instead of the 14 amps that was 2% of our battery bank size. This way we were able to charge the batteries up by an extra 25-30 amp-hours each day.

However, the Xantrex controller didn’t make this programming option obvious. Rather than having an input parameter for the current at which to switch from Absorb to Float like the Outback models have, you could enter only the size of the battery bank. The controller would then calculate what 2% of that value was and would use that value to switch from Absorb to Float.

So, we had to fool the controller by saying our battery bank was only 250 amp-hours rather than the 710 amp-hours that it actually was. Then it would switch from Absorb to Float when the current dropped to 5 amps (2% of 250) instead of at 14 amps (2% of 710).

This also could have been alleviated by throwing the system back into a Bulk charge, and in our first days of working with this system, there were many times when I wished there were a setting to force the charge controller to put the batteries back in the Bulk stage whenever I wanted. But unlike the Outback solar charge controllers, this Xantrex model did not have that option.

So, as you can see, the Xantrex XW MPPT 60-150 Solar Charge Controller takes a slightly different approach to the challenges of solar charging than the Outback models do. Here are the details:

The Xantrex XW MPPT 60-150 Solar Charge Controller charging algorithm is the following:

BULK: Deliver the maximum possible current to the batteries until they reach the Bulk voltage

ABSORB: Deliver as much current as necessary for the batteries to maintain the Absorb voltage. Transition to the Float stage when one of the following things happens:

  1. The current necessary to maintain the Abosrb voltage is 2% of the battery bank capacity
  2. The batteries have been in the Absorb stage for 2 hours (modifiable)
  3. The batteries have been at or above the Float voltage for 8 hours

FLOAT: Deliver enough current to the batteries to maintain the Float voltage.

EQUALIZE: The voltage and times for equalizing are user defined.

This charging algorithm is pretty straight forward, except for that odd 3rd way that the controller might switch from Absorb to Bulk. What’s going on there?

— What if the target voltages can’t be maintained — another technique!

That third trigger Xantrex uses for switching from Absorb to Float allows for the situation where the battery voltage has dropped below the Absorb voltage temporarily due to either clouds or shade or big loads in the RV or boat (vacuums or refrigerator compressors) drawing the voltage down for a while because the panels can’t deliver enough current. What it’s doing it that even if the batteries haven’t been at the Absorb voltage the whole time, as long as they have stayed above the Float voltage for at least 8 hours, they are considered ready to leave the Absorb stage and enter the Float stage.

Remember, the Outback solar charge controllers dealt with this same challenge of flaky sunshine by tracking how long the batteries fell below the Absorb voltage and then forcing the batteries to stay in Absorb for that same number of extra minutes to make up the lost time.

The Xantrex method is a little more simplistic than the Outback method, saying that as long as the battery voltage stayed above Float for 8 hours, they have been sufficiently charged and can switch to the Float Stage.

— Programming the charge controller for improved performance

As a recap, our goal was to keep the batteries in Absorb for as long as possible. So, I modified two of the Xantrex solar charge controller’s input parameters to allow this to happen:

  1. Pretend our battery bank was just 250 amp-hours instead of 710 so it would stay in Absorb down to 5 amps (modifying criteria #1)
  2. Increase the Absorb stage time limit from 2 hours to 8 hours (modifying criteria #2)

What these two programming changes ultimately did was they made the batteries stay in the Absorb stage for 8 hours, getting a healthy amount of current from the solar panels, unless the current happened to drop below 5 amps (2% of 250) before 8 hours was up.

This worked really well for 750 nights of anchoring out.



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We were extremely cautious with the AGM batteries in our boat and did not want to modify the solar charge controller’s default voltage settings for AGM batteries since AGM batteries are sealed and they can’t be charged at as high a voltage as flooded batteries (this is explained in more detail in Part 1 of this series).

The default charging voltages for AGM batteries on the Xantrex XW MPPT-60-150 Solar Charge Controller are:

  • Bulk: 14.3
  • Absorb: 14.3
  • Float: 13.4

* * * Lesson Learned * * *

Now that we have installed four Trojan T-105 Reliant AGM batteries in our fifth wheel and have been advised by the engineers at Trojan Battery to use Bulk and Absorb voltages of 14.7 volts on their AGM batteries instead of the 14.3 or 14.4 that most charging systems default to, I look back and realize I was probably too conservative with our boat’s AGM batteries.

If we had set the Bulk and Absorb voltage values to 14.7 instead of 14.4 (the setting I chose), then they would have charged faster (received more current from the charge controller) during those stages, and they would have won the daily race against the clock more easily. Obviously, more panels would have done the trick too, but finding unshaded deck space on a sailboat is tricky.

It only makes sense to program a battery charging system to the battery manufacturer’s specifications rather than assuming that the factory defaults on the charge controller are optimal. Afterall, charging system manufacturers — whether solar charge controllers, converters, inverter/chargers or engine alternators — will ALWAYS err far to the conservative side because they they are designing for a wide variety of battery brands and they don’t want to risk frying a customer’s batteries.

However, in the end, this might result in undercharging the batteries! Trojan Battery engineers have found that far more batteries die a slow death of chronic undercharging than a violent death of massive overcharging, so they prefer slightly higher charging voltages for their AGM batteries than are factory standard on many solar charge controllers, converters, inverter/chargers and engine alternators (with a caveat not to go to 14.8 volts or higher).



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We recently did a complete full-timer solar power installation on a friend’s motorhome. He specified the Morningstar TriStar TS-MPPT-60 Solar Charge Controller for his installation, so we had a chance to program it and work with it. This solar charge controller uses yet another methodology.

Morningstar TriStar MPPT 60 amp solar charge controller

Morningstar TriStar MPPT 60 amp solar charge controller

This solar charge controller is programmed via dip switches and the charging stages are indicated by LED lights rather than a digital readout. You can also purchase the additional TriStar Remote Digital Meter that has a two line LCD display similar to the 2-line and 4-line displays on the Xantrex and Outback models described above.

Separating the charge controller from the display is a great idea. It allows you to install the display inside the RV or in the boat’s cabin where you can read it easily and mess with its buttons whenever you wish. Yet you can still place the charge controller itself right next to the batteries where it needs to be (the cable going from the batteries to the charge controller must be as short as possible).

Our friend did not purchase the remote meter, but we found the system was easy enough to set up without it. The dip switches were a clunky interface, but that would be improved with the buttons and digital display of the remote meter. The lack of a digital readout made it difficult to know the details about the voltages and currents of the panels and batteries in the system. However, our friend did not plan on programming the solar charger any further, and he already had a battery monitor in his coach, so he had a way to monitor the battery voltage easily.

Here are the details on the charging algorithm:

The Morningstar TriStar TS-MPPT-60 Solar Charge Controller multi-stage charging algorithm is the following:

BULK: Deliver the maximum amount of current possible until the batteries reach the Bulk voltage.

ABSORB: deliver as much current as necessary to keep the batteries at the Absorb voltage until the following thing happens:

  • 2 to 2.5 hours has gone by (depending on battery type)

If the batteries fell below 12.5 volts during the previous night, then extend the Absorb stage by 30 minutes.

FLOAT: Deliver as much current as necessary to keep the batteries at the Float voltage. If the batteries are drawn down below the Float voltage for an hour or more due to big loads in the RV or boat (vacuum, power tools, microwave) or due to sudden cloud cover, the charge controller will switch back to Bulk mode and start the cycle over again. If the batteries fell below 12.3 volts during the previous night, then the solar charger will not enter the Float stage the following day.

EQUALIZE: The voltage and duration of the Equalization stage is determined by the battery type selected and is started manually.

This is yet another creative approach to the various problems caused by the unreliability of sunshine. The idea of setting up the charging parameters today based on the lowest voltage the batteries reached overnight is cool, since that is truly the biggest determining factor for how much charging the batteries need right now.

However, note that there is no criteria for switching from Absorb to Float based on the current falling below a minimum value as with the other charge controllers. There is also no provision for lengthening the Absorb stage if the Absorb voltage can’t be maintained, although there is if the Float voltage can’t be maintained.

The Absorb, Float and Equalize voltages are assigned in this controller when you select the battery type. AGM batteries are assigned:

  • Bulk/Absorb: 14.4
  • Float: 13.7

There seemed to be an option to override those values with custom values, however, it wasn’t clear how to enter the actual voltages using the dip switches. The TriStar Remote Digital Meter might provide more programming flexibility.

The Morningstar does come with PC based software, and it is possible to connect the solar charge controller to your in-house ethernet network via the controller’s ethernet port or to connect it using a wireless router. However, for me, that adds a level of complexity that isn’t really necessary.

There are just a few parameters to enter on any charge controller, and just a few values to monitor, and those only need to be monitored occasionally. Having a menu driven screen interface built into the charge controller rather than getting my computer involved in the action is worth a lot to me.



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As you can see, there is a significant variation in how the different manufacturers of solar charge controllers tackle the challenge of creating an algorithm to charge the batteries, given the vagaries of sunshine. All of the solar charge controllers described here get the job done, it’s just that the methodology varies and the ease of use and programmability of the units differ.

If you want to get the most out of your solar charge controller, the most important thing is to know what your battery manufacturer’s recommended charging voltages and time limits are, that is, what their preferrred Bulk, Absorb and Float voltages are and how long they want the batteries to remain Absorb. Then program the solar charge controller accordingly.

The reason I chose the Xantrex XW MPPT-60-150 Solar Charge Controller for our boat rather than purchasing another Outback charge controller like the one in our RV (the nice new FlexMax 60 was on the market by then) was that the Outback has a fan in it. I was concerned that in the hot tropical climates where we would be sailing, the fan would likely run a lot and might fail. I didn’t want any moving parts! I chose the Xantrex because it is cooled by large cooling fins instead of a fan.

In hindsight, the Outback charge controllers are rated to operate at up to 104 degrees, and the cabin of our boat never got that high. Probably an Outback charge controller would have held up just fine. The Morningstar with its Remote Digital Meter is a neat idea for separating the charge controller and the digital display. However it does require a few more installation steps to mount the remote meter and run the cable from the charge controller location to the remote meter location. It also has a simpler overall charging algorithm, which could be a pro or a con depending on your preference.


The next — and final — article in this series takes a look at what happens when two battery charging systems are running simultaneously. That is, what happens if you have solar power and you plug into shore power or turn on the boat engine?

To continue to the next article in this series, click here:

Solar and Shore Power or Engine Alternator Battery Charging Combined

4-Part Series on RV and Marine Battery Charging Systems:

Related posts about batteries, solar power and living off the grid in an RV or boat:

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Our most recent posts:

More of our Latest Posts and Quick Pics are in the top MENU above.New to this site? Visit RVers Start Here to find where we keep all the good stuff!!

RV Converter, Inverter/Charger, and Alternator Battery Charging Systems

This article discusses battery charging systems that are “artificially powered” by electricity or an engine (as opposed to sun or wind power) and the methods these systems use to chargeso RV and marine batteries. It is the second post in our four part series on RV and Marine Battery charging systems.

Converter Inverter-Charger Engine Alternator Battery Charging Systems

The first article in the series, RV and Marine Battery Charging Basics, explains how batteries are charged and describes the concepts of single stage and multi-stage charging. The third and fourth articles in this series are:

You can navigate to specific parts of this article with the links below:



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There are two basic types of multi-stage chargers for RVs and boats: those that are “artificially powered,” either by electricity, by an engine or by a generator, and those that are “naturally powered” by the sun (or wind). Note: Although this series doesn’t discuss wind charging systems, the same principles apply.

What is the difference?

Ability to Deliver the Maximum Rated Current

The biggest difference between these two types of charging systems is that artificially powered charging systems — converters, inverter/chargers and alternators — can all deliver the maximum amount of current they are rated for as soon as they are turned on. In contrast, “naturally powered” chargers may or may not be able to deliver their maximum rated current when called upon to do so.

Yamaha 2400i portable gas generator

Yamaha 2400i portable gas generator
As long as there’s gas, it’s good to go.

Solar charge controllers can deliver their maximum rated current only if they are connected to a large enough solar power array and that array is exactly perpendicular to full sunshine. Unfortunately, no matter how big the solar panel array is, these charging systems spend most of their time operating in sub-optimal conditions when the sun is low in the sky or filtered by clouds or totally absent because it is nighttime.

In addition, if a big appliance is turned on in the RV or boat while the batteries are being charged, the artificially powered charging systems can meet the challenge and provide the current that is needed (up to their rated current output and up to the limits of the power source) to keep the batteries at their target charging voltage.


The sun’s out — yay!
We can start charging!

However, solar charge controllers may or may not be able to meet the challenge, depending on the time of day and amount of cloud cover. In fact, if the current draw is big enough, not only will the solar charge controller fail to keep up with the sudden demand, but the net effect on the batteries may be that they are temporarily being discharged a little bit rather than charged.

Therefore, solar charge controllers have a lot of extra complexity built into their charging algorithms so they can handle the situations where, for whatever reason (lack of sun and/or too much demand from the appliances in the RV or boat) they aren’t actually charging the batteries but are just slowing down the discharge rate!

Ability to Restart the Charging Process with the Bulk Stage

Artificially powered charging systems can all be turned on or off with the flick of a switch. Most systems will test the battery voltage to see if they should jump into the Bulk stage as soon as they are turned on. This gives you a way to force the batteries into the Bulk stage and start the charging process from scratch.

Solar charge controllers operate 24/7, and they rely on an internal algorithm to determine when it is morning and time to start the Bulk charging stage. Not all solar charge controllers are designed to have an easy way for the user to put the batteries in a Bulk charging stage at any time of day other than dawn.




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Many artificially powered charging systems are programmable, but usually the choices are minimal. If they can be programmed at all, it is generally done with dip switches or simple buttons. In contrast, big solar charge controllers are complex enough and have so many programmable options that they often have a screen display and a menu driven interface.

Some charging systems have preset groups of voltage values, and all you can select is whether your batteries are Flooded, AGM or Gel. The charger then assigns voltage values for the charging stages based on battery type. In this case, the charging system manufacturer is guessing what voltages are appropriate for your batteries. The battery manufacturer may have different specs!

The most sophisticated (and expensive) charging systems allow you to enter any value you want for the individual charging voltages as well as the length of time to remain in the Absorb stage and other values as well.

Even if you don’t study the charging algorithm that is used by the charging systems on your RV or boat, it is worthwhile to find out what the default voltages are for the Bulk, Absorb and Float stages are on each device.



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There are rules of thumb for what the charging voltages should be for the various battery types, with flooded batteries requiring higher charging voltages than AGM and Gel batteries. The general consensus I found in my research was that flooded batteries preferred a Bulk/Absorb voltage in the range of 14.6 – 14.8 volts while AGM and Gel batteries prefer to be around 14.4 volts.

Because of this general consensus, I set up all the charging systems on our boat with Bulk and Absorb values around 14.4 volts so we wouldn’t fry our four Mastervolt 4D AGM batteries house batteries and our Group 27 start battery.

Needless to say, I was quite surprised when we installed our four new Trojan T-105 Reliant AGM 6 volt batteries in our trailer, that the engineers I spoke with at Trojan Battery recommended we set the Bulk and Absorb stages of our charging systems to 14.7 volts. They said the vast majority of battery failures are from chronically undercharged batteries, so they preferred that their AGM batteries be charged at this higher voltage.

I never spoke with anyone at Mastervolt back in our cruising days, and their documentation didn’t specify charging voltages. In hindsight, perhaps we should have been charging the batteries on our boat to higher Bulk and Absorb voltages. They would have charged faster, which would have been awesome, especially on solar, because our solar panel array was a little small (555 watts), and getting the batteries fully charged by day’s end was a challenge unless we turned off our DC freezer.

Lesson learned: If you can’t find your battery manufacturer’s recommended charging voltages in their documentation, give them a call!

The next sections take a look at a few artificially powered charging devices we have used and the algorithms they employ for battery charging.




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Most trailers are equipped with a converter to charge the batteries from shore power (via electric hookups or a portable gas generator). The shocking thing about these converters is that many of them are just single stage trickle chargers. (Note: if you are confused about what converters and inverters are, click here).

We had never thought much about our converter, because we use it very rarely. We don’t ever get electrical hookups, so our converter is used only when we fire up our gas generator, which happens just a few times a year. We had always assumed that the Atwood SRV 55 amp converter that came with our Hitchhiker II LS fifth wheel was a multi-stage charger. However, we discvoered a few months ago that this converter is actually a single stage trickle charger. It brings the batteries up to 13.4 volts and leaves them there indefinitely, as long as the converter has AC power supplied to it.

This is startling for two reasons.

First of all, since we boondock all the time, this means that whenever we turn on our generator to charge our batteries (after a few days of stormy weather), rather than giving the batteries a fast blast of Bulk charge followed by Absorb and Float, the batteries are immediately put into a Float stage and left there. Rather than getting a quickie does of lots of current and then trailing off to less and less current, the batteries get an anemic amount of current the whole time the generator is running.

What a waste of fuel! And who wants to listen to that noisy thing for that long! Rather than taking an hour or two to charge the batteries completely, it could take 8 hours or more. Ugh!

Secondly, single stage converters like this Atwood don’t exercise the batteries at all when they are left on shorepower via electrical hookups, and the batteries deteriorate more quickly. This is an important consideration for an RV that is plugged into shore power month after month. It is important for batteries to go through the Bulk and Absorb stages periodically.

We decided to replace our factory-installed single-stage Atwood 55 amp converter with an Iota DLS 90 converter / IQ4 smart charger a few months ago so that on the days that we use our generator we could use it for a very short time rather than running it all day.

Besides wanting a true multi-stage charger that could load the batteries up with a lot of current at the beginning of the charge cycle, we also realized our old factory installed converter was too small.

Remember that 25% rule for sizing batteries and chargers from the last post? Our converter had been sized for the two Group 24 12-volt batteries (total capacity 140 amp-hours) that had come with our RV, and we had upgraded to four Trojan T-105 Reliant AGM 6 volt batteries which gives us a total capacity of 435 amp-hours.

Our new Iota DLS-90 / IQ4 is a 90 amp converter which is much more appropriately sized to the new battery bank.

And what a world of difference there is between these two converters!

The Iota DLS 90 / IQ4 is far more sophisticated. It puts the batteries into a true Bulk charge state as soon as AC power is available (for us, that is when we turn on the generator with the shorepower cord plugged into it). Then, after cycling through Absorb to Float, it keeps the batteries in the Float stage for seven days (not applicable to us with our generator, but important for folks who get electric hookups), and then it cycles them through Bulk and Absorb again.

The multi-stage algorithm that the Iota DLS 90 / IQ4 uses is the following:

BULK: Whenver the batteries are below 12.8 volts (i.e., when first plugging into shore power or when a bunch of appliances are turned on in the RV or boat) deliver the maximum current possible (up to 90 amps DC) until the batteries reach a voltage of 14.6 volts, then switch to Absorb. If they don’t reach 14.8 volts within four hours, switch to Absorb anyways.

ABSORB: For eight hours, deliver enough current to hold the batteries at 14.2 volts.

FLOAT: For seven days, deliver enough current to hold the batteries at 13.6 volts. Then go through the Bulk and Absorb stages before resuming the Float stage.

The system is fully automatic and none of these values or times are programmable.

Note: For readers who have studied the spec sheets on the Iota DLS-90/IQ4, this outline differs slightly from what you read. I had a lengthy conversation with an engineer at Iota who explained the details of how this converter works. The documentation refers to the weekly return to Bulk and Absorb as an “Equalization” stage, but the voltages and times are actually those of the Bulk and Absorb stages. As noted in the first post in this series, equalization is generally done at 15 volts or more for less than 8 hours. In addition, the documentation describes the converter’s power supply ramping up to 14.8 volts during Bulk, but doesn’t explain that the actual trigger point that switches the batteries from Bulk to Absorb is 14.6 volts.

Using the Iota DLS 90 / IQ4 The First Time

A few weeks ago we endured several days of gray skies and rain while we were driving from Florida into southern Georgia. Our solar panels were producing very little current, and our new Trojan T-105 Reliant AGM batteries were becoming depleted. There was no sign of sun in sight.

We set up our Yamaha 2400i portable gas generator and plugged our shore power cord into it. We clamped the jaws of our trusty clamp-on ammeter around one of the battery cables and were truly astonished to see 67 amps going into the batteries. Yowza!! Within two hours the batteries had accepted roughly 100 amp-hours of charge and we turned the generator off. Our old converter would have taken about 8 hours or more to do the equivalent.




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Many motorhomes and cruising boats are equipped with an Inverter/Charger to charge the batteries when the RV or boat is plugged into shore power. Our Hunter 44DS sailboat was equipped with a Xantrex Freedom 25 inverter/charger which was factory installed in the boat. Xantrex has since become Schneider Electric, and a comparable model being sold today is the Schneider Electric 2500 watt inverter/charger. I haven’t found an online manual for it, so I don’t know if the charging algorithm or programmability of the unit has changed.

Schneider Electric 2500 watt inverter : charger

Schneider Electric 2500 watt inverter/charger
This is the updated model of our Xantrex Freedom 25 Inverter / Charger
(ours was buried under a settee and impossible to photograph!)

Unlike many converters, most inverter/chargers are multi-stage chargers. Our Xantrex Freedom 25 had minimal programming capabilities. You could enter the battery type (Flooded, Gel or AGM), and the voltages for the charging stages were automatically assigned according to the battery type you selected. You could not enter any other values. We had AGM batteries, and the Xantrex inverter/charger assigned them defaults of:

  • Abosrb: 14.3 volts
  • Float: 13.3 volts

If you wanted different voltages, you could select the Flooded or Gel values instead simply by indicating that your batteries were Flooded or Gel, even if they weren’t.

The multi-stage charging algorithm for the Xantrex Freedom 25 inverter/charger is the following:

BULK: Deliver the maximum current possible until the Absorb voltage is reached

ABSORB: For up to 3 hours, deliver as much current as needed to keep the batteries at the Absorb voltage. If the current necessary to keep the batteries at the Absorb voltage drops below 15 amps before the 3 hours is up, stop charging and let the battery voltage settle down to the Float voltage.

FLOAT: Deliver enough current to hold the batteries at the Float voltage., and keep the batteries at the Float voltage indefinitely.

EQUALIZE: Whenever you want to equalize the batteries, you can manually put them into an Equalize charging stage. The inverter/charger will deliver enough current to bring the batteries up to 16.3 volts and will keep them at that voltage for 8 hours.

Notice how different the Xantrex inverter/charger is than the Iota DLS 90 / IQ4 Converter!. Both the voltages and lengths of time are quite different.

Even more interesting, however, is where the heck did that 15 amp thing come from for switching from Absorb to Float?

As a rule of thumb, it is thought that when the batteries need less than 2% of the amp-hour capacity of the entire battery bank in order to maintain the Absorb voltage, then they are pretty close to full charge and can be put in the trickle charge Float stage.

This 15 amp switchover is an attempt at implementing this 2% rule. However, because the 15 amp value is not modifiable, the assumption is that the battery bank is 750 amp-hours (15 is 2% of 750). That’s quite an assumption! More sophisticated charge controllers allow you to program the current at which you want the system to switch from Absorb to Float.

Our boat’s battery bank was 710 amp-hours, so a more accurate number would have been 2% of 710, or 14 amps. 15 amps versus 14 amps — big deal, right? It’s true, for an inverter that is going to be running 24/7 when you are plugged into shore power, that slight difference is not significant.

But if you are using the inverter/charger with a generator (to supplement solar power during stormy days), you might want to stay in the Absorb stage for the full 3 hours rather than dropping into Float as soon as the current dips below 15 amps!

Also, as I’ll show in the next post in this series, 15 amps was still much too high a current — in our case — to switch from Absorb to Float when we charged our boat’s battery bank with our solar charge controller. We wanted the switch-over current from Absorb to Float to be only 5 amps.




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Cruising sailboats and motorhomes are equipped with an engine alternator that charges the batteries. Our sailboat had a 100 amp Balmar alternator with an ARS-4 Smart Charger which was a multi-stage voltage regulator.

Balmar 100 amp engine alternator

Balmar 100 amp diesel engine alternator

The multi-stage charging algorithm the ARS-4 Smart Charger uses is the following:

BULK: For 36 minutes deliver maximum current until the batteries reach the Bulk voltage. If the Bulk voltage is not attained in 36 minutes, then continue delivering that same current for 6 more minutes. If, again, the Bulk voltage has not been reached, continue for 6 more minutes and check again. Repeat this cycle until the Bulk voltage is reached.

ABSORB: For two hours, deliver enough current to keep the batteries at the Absorb voltage. If after two hours the batteries are not at the Absorb voltage (due to large current draws from systems on the boat or RV), check every six minutes until the Absorb voltage is achieved.

FLOAT: For six hours, deliver enough current to keep the batteries at the Float voltage. After six hours, increase the current being delivered to the batteries to bring them up to the Abosrb voltage and keep them at that voltage 36 minutes. Then return to Float for six more hours. Repeat this cycle indefinitely.

EQUALIZE: The equalizing stage is started manually and you can choose the voltage and time limit.

This charging system is quite programmable. The user can enter the length of time of each stage, and all the voltages can be programmed to any value as well. The factory default voltages are:

  • Bulk = 14.1 volts
  • Absorb = 13.9 volts
  • Float = 13.4 volts

Notice that with this particular engine alternator the batteries are not left in the Float stage indefinitely. Instead, they are put into Float for six hours and then in Absorb for 36 minutes, cycling between those two stages indefinitely.

How long is “indefinitely” when it comes to running a boat’s engine, anyway? Well, we had lots of 24 to 55 hour passages on our cruise where the engine ran nonstop. The alternator cycled between Absorb and Float quite a bit during those passages.




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One really important aspect of using an alternator to charge a large battery bank, especially if the engine will be running when huge loads are put on the batteries (like the anchor windlass or power winches), is the 25% rule of thumb I mentioned in the first post of this series: the rated output current of a charger should be roughly 25% of the capacity of the battery bank.

Most cruising boats have very large battery banks. Ours was 710 amp-hours, and we knew lots of cruisers with 600 amp-hour banks all they way up to 1,000 amp-hour banks. For us, 25% of our 710 amp-hour battery bank calculates to 177, so our alternator needed to be a 180 amp alternator to be sized correctly.

The problem is that most alternators over 100 amps require a double pulley system on the engine. That’s complicated, and very few cruisers choose to go that route. Instead, they tend to limp along with undersized alternators.

And what is the most common system failure we saw sailors experiencing on their cruising boats? Alternators!

Not only are most cruising boat alternators undersized, most alternators are called upon to power the anchor windlass, lifting a 60 or 70 lb. anchor along with 100 to 300 feet of stainless steel chain from a depth of 20 or 30 feet. Frequently, it does this in pre-dawn hours of the morning, after the sailors have spent an evening with lights and laptops running and maybe watching a movie. The boat’s batteries are depleted and the solar panels are still asleep and aren’t helping out. It’s like asking a weak and starving person to move furniture.



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The manufacturers of converters, inverter/chargers and diesel engine alternators each approach the methodology of multi-stage charging in unique ways, and the charging systems described on this page are just a few examples from our own personal experience.

If you have the time and the inclination, read the user manuals of the charging systems on your RV or boat, find out what your battery manufacturer gives for recommended settings, and set your charging systems up accordingly.

To continue to the next article in this series, click here:

Solar Charge Controllers – Optimizing Battery Charging from the Sun

4-Part Series on RV and Marine Battery Charging Systems:

Related posts about batteries, solar power and living off the grid in an RV or boat:

Never miss a post — it’s free!

Our most recent posts:

More of our Latest Posts are in the MENU.
New to this site? Visit RVers Start Here to find where we keep all the good stuff!!

RV and Marine Battery Charging Basics

RV and marine batteries can be charged using many different kinds of charging systems, and understanding the way these chargers work can make a huge difference in whether or not you get the most out of them.

Not only are there differences between single stage charging and multi-stage charging, but in our experience, no two multi-stage chargers use the same charging algorithm. Also, the ability to program the settings on each charging system varies a lot from unit to unit.

Furthermore, some chargers, like converters, inverter/chargers and engine alternators, are powered by a consistent power source that allows them to operate at their maximum ratings at any time of day or night. Others, like Solar Charge Controllers and wind chargers are powered instead by an energy source that comes and goes.

In our eleven years of living off the grid in an eleven years of living off the gridlesstraveled.us/hitchhiker-2/” title=”2007 NuWa Hitchhiker 34.5 RLTG fifth wheel trailer RV” target=”_blank”>RV and a sailboat, we have relied on a wide variety of systems to charge our batteries. At times, we have used a converter, inverter/charger or engine alternator in conjunction with our solar charging system, and we’ve learned a lot about these systems and how to make them work together harmoniously.

The four parts in this series cover the following:

1. Battery Charging Basics – (this article) – Explains single-stage charging and multi-stage charging and explores the ways that certain products implement a multi-stage charging algorithm (no two are alike).

2. Converters, Inverter/Chargers and Engine Alternators – Discusses the differences between converters, inverter/chargers and engine alternators, which I lump together as “artificially powered” charging systems

3. Optimizing Solar Charge Controllers – Examines these “naturally powered” solar charging systems whose power source is the sun, which is very unreliable.

4. Combining Solar Power with Shore Power or an Engine Alternator – Reveals some of the subtleties of solar charging and gives some ideas for how to get the most out of a solar charge controller when it is run alongside a converter, inverter/charger or engine alternator.

This first post in the series has many sections, and you can easily navigate directly to them by using the links below.


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Many people enjoy RVing and cruising without every relying on the house batteries for more than a few hours or an overnight. However, some of the joy of traveling with an RV or boat is being independent and free, and there is no better way to experience that freedom than to spend a few nights on your own, camped on public land or anchored in a quiet cove. Having well charged batteries makes a big difference in how comfortable you’ll be. Also, understanding the gear that charges your batteries can go a long way towards making sure your batteries perform optimally and are in the best condition possible.

In our household, Mark is the one who does the installation work while I (Emily) am the one whose head is in the clouds somewhere thinking about theory and design. When Mark asks me to hand him a box end wrench while he’s peering into some dark corner of our boat or RV, I go rummaging around in all our boxes and stare at all the wrenches and wonder what he wants.

When the installation is finished, however, Mark washes up and washes his hands of all concerns about it. If he flips the switch and it runs, then he’s off the hook. “The factory settings are fine!” He tells me. “Set it and forget it!” But that’s the time when my curiosity just begins to get going. I want to know how it works, what makes it tick, and how it’s designed.

I admire Mark’s carefree and trusting attitude, and truly:

Your batteries will probably be fine if you click off this page right now and go read something more amusing.

But for those folks out there who just can’t pry their minds away from these things, I hope this four-part series will give you some food for thought. I make no claims to be an expert and am simply passing on the things I’ve observed and learned.



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In order to have a consistent standard for rating how much power a battery can store, manufacturers indicate how many amps of current draw it takes to drain their battery to 80% discharge (down to 1.75 volts per cell, or 10.5 volts for a 12 volt pattery) over a given time period. For “deep cycle” batteries this time period is 20 hours, and it is called the 20 hour amp-hour rating.

Batteries are also manufactured in standard sizes, including Group 24, Group 27, Group 31, 4D and 8D, for 12-volt deep cycle batteries, and GC2 for 6-volt batteries that power golf carts. The ratings are given in the manufacturer’s specs for the batteries and is often shown on a sticker on the battery itself.

These Amp-Hour ratings can range from about 70 amp-hours for a single 12-volt Group 24 battery to 220 amp-hours for a pair of 6-volt GC2 batteries to 230 amp-hours for a single 12-volt 8D battery.

Wait, what was that about a PAIR of 6-volt batteries??

When batteries are wired in series, the current draw remains the same while the voltage of the pair of batteries doubles. For this reason, when a 6-volt golf cart battery is rated with a 220 Amp-Hour capacity, wiring it to a second 6-volt battery to create a virtual 12-volt pair does not double its Amp-Hour capacity. Those two 6-volt batteries wired in series have the same old 220 Amp-Hour capacity that the single battery did.

The physical size of these battery types varies too, with a Group 24 12-volt battery weighing as little as 47 lbs and an 8D 12-volt battery weighing as much as 160 lbs. 6-volt golf cart batteries are the same width and depth as 12-volt Group 24 batteries, however they are a little taller and heavier, and they offer a lot more storage capacity per pair than a single 12-volt Group 24 battery does.

RVs are typically sold with Group 24 or Group 27 size batteries, either a single battery or two.

To beef up an RV’s battery bank, the easiest and most effective upgrade is to replace the single 12-volt battery with two 6-volt golf cart batteries wired in series. This will typically increase the battery capacity from about 70 amp-hours to 220 amp-hours.

An alternative upgrade option, if there isn’t enough height in the battery compartment for 6-volt batteries, is to add a second 12-volt Group 24 battery (if the first battery is new) or to replace the single 12-volt battery with two 12-volt batteries for an overall capacity of around 140 amp-hours.



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In essence, discharged batteries are a lot like hungry people. If you’re super hungry, you’ll dive into a big dinner with gusto. If you eat too much too fast, you’ll get sick! If you eat at a normal pace, you’ll slow down as the meal progresses, and eventually you’ll be full and you won’t want any more food.

Batteries are very similar. The food they want is current (amps), but if you feed them too much they get damaged!

Discharged (hungry) batteries can accept a lot of charge (current) at first. However, as they become more and more charged, they accept less and less current. A fully charged battery is around 12.7 volts. A fully discharged battery that still has enough life in it to be able to be fully charged again is around 11.6 volts. RV and marine house batteries will last longest if they are always kept above 12.0 volts, preferably above 12.1 volts.

The way a battery is charged is that some external charging device temporarily forces the battery to a higher voltage than its “fully charged” voltage of 12.7 by feeding it lots of current.

The fastest way to charge a battery is to put as much current into it as possible. As long as the charger is delivering lots of current, the battery’s voltage will rise. The charger itself must be at a higher voltage than the batteries to do this. If the charger is around 13.5 volts, it can force a modest amount of current into the batteries. If it is around 14.5 volts, it can force in a lot more current.

During charging, the battery voltage will rise into the high 12 volt range, then it will move into the 13 volt range, then 14, and so on. It takes time for the battery’s voltage to rise as it is fed current. A more deeply discharged battery will take longer to reach a given voltage than a minimally discharged battery will.

If the charger is turned off so no current is going into the battery, the battery will gradually fall back to is own “internal” voltage. This may take 15 minutes or more. If it has been charged for a while, this voltage will be near or at the “fully charged” value of 12.7 volts. If it hasn’t been charged long enough, the battery’s internal voltage will be lower than that.

For instance, if a battery is partially discharged to 12.4 volts, the way to get it charged back to 12.7 volts is for a charging system to give it a bunch of current and temporarily force it up to some higher voltage in the 13 to 15 volt range. The charging system itself will need to be at a higher voltage than whatever voltage it is trying to get the battery to.

After a while, when the charging system is turned off and the battery is allowed to settle back down to its own internal voltage, it may drop back to 12.7 volts, in which case the battery is fully charged. However, the battery may settle back down a little lower — perhaps to 12.5 volts — which means it could use a little more charging to reach a fully charged state.


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The following chart shows the different voltages batteries have when they are charged or discharged. If you have nothing running in the rig (no computers running, no TV, no vacuum or toaster, etc.), you can measure the battery voltage using a hand-held voltmeter in DC volts mode by placing the two probes on the two battery terminals. This is what we do. You can also install a simple volt meter on the wall of your coach or install a fancier battery monitor.

Battery charge state chart

Data from Trojan Battery, rounded to tenths for easy memorizing.
Note that the values decrease by 0.1 volt for each 10% drop until 60%.

If the battery has just finished charged for a few hours, there will be a surface charge on the metal plates inside of it which will raise the voltage by a tenth of a volt or so. Running an appliance for a few minutes in the RV or boat will remove that surface charge so you can see the battery’s true internal voltage.

On the other hand, if a lot of appliances are running in the rig, current will be being drawn out of the battery and the battery’s voltage will be lower than its true internal voltage. Turning everything off and waiting a few minutes will bring the battery back to its true internal voltage.


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Batteries are filled with thin metal plates and battery acid (electrolyte). As a battery’s voltage is raised, the internal chemical reactions inside the battery make the electrolyte heat up. If the voltage is raised high enough for long enough, the acid begins to release gases (like hot water beginning to steam), and eventually the acid begins to boil.

Trojan Reliant 12 volt AGM battery metal plates inside

Looking down into the battery cells of four 12 volt Trojan flooded batteries
before the electrolyte is poured in.

Raising a 12 volt battery to a voltage in the high 14’s or more for a few hours is enough to make the batteries begin to start gassing. Reducing the voltage to the mid-13 volt range stops the gassing.

Some trickle chargers don’t allow the battery voltage to rise above the mid-13 volt range to avoid having the batteries begin gassing. However, the less a battery’s voltage is raised, the less current will go into it and the less the battery will be charged after a given number of hours. It is possible for the battery to become fully charged at a lower voltage, but it will take much longer.

The engineers at Trojan Battery have told us that almost all the dead batteries they have studied over the years have been chronically undercharged. Overcharging is a much less common problem.

When batteries are chronically undercharged, they develop lead sulfate crystals on the lead plates inside the battery. This is called sulfation. This material reduces the battery’s capacity, and it can even form a bridge from plate to plate, creating an internal short and rendering the battery useless.

With flooded (wet cell) batteries, raising the battery voltage very high (15 volts or more) for a few hours heats up the electrolyte until it gasses and boils and sloughs the sulfate material off the metal plates. The material then settles on the bottom of the battery underneath the plates where it doesn’t risk forming a bridge between the plates. This process is called Equalizing.

Equalizing is done only on wet cell (flooded) batteries. Gel and AGM batteries are sealed and cannot release gasses, so they can actually be damaged by charging them at a very high voltage in this manner.

There is no definitive moment when a battery is fully charged. It is similar to feeling full at the end of a meal. After a great dinner, you can usually find room for a yummy sliver of pie, or maybe just one bite of your spouse’s pie, but you can definitely leave the table feeling full without having any pie at all. RV and marine batteries are much the same in that they can usually accept another fraction of an amp of current from a charger even though they are essentially full charged.



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Batteries need to be used, and the worst thing that can happen to a battery is that it doesn’t go through regular discharging and charging cycles. Like a person who needs to exercise to to burn calories and give them a good appetite so they can consume some nutrition, batteries need to be used (discharged) and then charged up again to maintain peak health.

RVs and boats that are stored without being plugged in to shore power for long periods of time will slowly have their batteries discharge completely over a period of months. That’s not good! There’s nothing like coming back to the RV or boat to find dead batteries. However, if the RV or boat is left plugged into shore power to avoid this problem, even though the batteries will be fully charged at the end of a few months, they may still die a premature death due to not getting enough exercise and not being used.

For RVs and boats left on a charger for months at a time, whether or not the owners are living on board, a charger that periodically raises the battery voltage above a trickle charge will help prolong the battery life. Occasionally unplugging from shore power and running some appliances for a few hours will give them a good workout too.

The engineers at Trojan Battery have spent years studying car batteries that have died. The most common failure they find is what they call “Lot Rot” caused by cars that are used infrequently and drive only short distances.


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Battery chargers come in all sizes with maximum current output ratings that range from a few amps to hundreds of amps. One rule of thumb for sizing a battery charger to a battery bank is for its maximum current output rating to be roughly 25% of the amp-hour capacity of the battery bank.

RVers and sailors that plan to boondock or anchor out a lot tend to replace the factory installed battery banks with bigger ones. In this case, it is worthwhile to review the sizes of the factory installed charging systems to make sure they will be big enough to charge the new battery bank efficiently.

For instance, an RV or boat shipped with two Group 24 12 volt batteries that have a combined amp-hour capacity of 140 amps wil be fine with its factory installed 55 amp charging system. But if those batteries are upgraded to four 6 volt golf cart batteries with a combined capacity of 450 amp-hours, a larger charging system will perform better.


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A single stage charger will deliver enough charge to keep the batteries at a set charging voltage indefinitely. At first, the batteries will require a fair amount of current to be able to maintain that voltage. But as time goes on they will need less and less current to maintain that voltage. If the charging system is turned off, they will drop down to their own “internal” voltage. If that internal voltage is 12.7 volts, then they are fully charged. If not, they need to be put back on the charger!

This kind of single stage charging system works okay, but it is inefficient and risks undercharging or overcharging the batteries.

Automotive battery chargers generally charge the batteries at a high voltage (in the mid-14 volt range). This is fine for a while, but the batteries can’t be left on this kind of charger for very long or they will overcharge. An alternative is a single stage trickle charger that charges the batteries at a modest voltage (in the mid-13 volt range). This is how a lot of cheaper RV battery chargers (converters) work.

The problem with a single stage trickle charger is that it takes a very long time for the batteries to reach full charge. That’s okay if you are plugged into shore power for a few days, but if you are running from a generator, do you really want to run it for 12 hours just to get the batteries charged?

Also, a single stage charger never pushes the batteries up to a higher voltage, something that is considered helpful for prolonging battery life.



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A more efficient charging system is to give the batteries a lot of current at first, while they are most depleted, and then to back off, forcing less current into them once they are fairly well charged up. This is what multi-stage charging systems do.

Multi-stage chargers generally have three stages: Bulk, Absorb and Float.

Bulk Stage

In the Bulk stage, the battery is given as much current as the charging system can deliver. As the batteries accept this charging current, their voltage slowly rises. Eventually the batteries reach the “Bulk Voltage” which is something in the range of 14.3 to 14.8 volts, depending on the charger, the battery manufacturer’s recommendations and/or your own personal choice.

Absorb Stage

At this point the multi-stage charger switches tactics. Rather than giving the batteries as much current as the charger can deliver, the charger instead gives them only as much current as it takes to keep them at a particular voltage known as the “Absorb Voltage” (which is also usually between 14.3 and 14.8 volts). While the batteries are held at the Absorb voltage, they are in the Absorb stage (this is called the “Accept” stage by some manufacturers, but is more commonly known as the Absorb or Absorption stage).

The idea in the Absorb stage is that rather than force feeding the batteries all the current the charging device can deliver, the batteries are given just enough to keep them at the Absorb voltage. At first, this is pretty much the same amount of current they were getting in the Bulk stage. But after a while, the batteries don’t need as much current to be able to maintain the Absorb voltage. So, over time during the Absorb stage, the multi-stage charger delivers less and less current to the batteries, and the batteries just “hang out” at the Absorb voltage, getting force-fed a steadily decreasing amount of current.

Float Stage

At the end of the Absorb stage (and what defines “the end” of the Absorb stage is one of the areas where manufacturers and devices differ the most), the multi-stage charging system switches tactics again. Now, rather than holding the batteries at the relatively high Absorb voltage of 14.3 to 14.8 volts, the charger will hold the batteries at a much lower Float voltage in the range of 13.3 to 13.6 volts.

Of course, the batteries will require a lot less current to maintain this lower voltage, so the charger will now be delivering a much lower current. And again, as time progresses, the amount of current that the batteries need to maintain the Float voltage will diminish. At first, the batteries will need a fair bit of current to maintain the Float voltage, but as the hours go by they will require less and less. As with the Absorb stage, the batteries will just “hang out” at the Float voltage during the entire Float stage.

When the batteries reach the Float stage they are considered to be pretty nearly fully charged. If the charger is turned off at this point, the batteries will eventually settle down (after a few minutes) to their own internal voltage, and that voltage will be around 12.7 volts, indicating that they are fully charged.



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Of course, the multi-stage charger could be turned off at any time during the charging process, before the batteries are fully charged. Why? Well, during Bulk or Absorb or Float you might unplug the shore power cord so the RV or boat can go somewhere, or you might turn off the generator for quiet hours in the campground, or the sun might set, making the solar panels ineffective, or an engine with a built-in engine alternator might be turned off when the sails are raised on a sailboat or the motorhome is parked, etc.

These are all arbitrary events that could happen at any point in the multi-stage charging process.

When this happens, the batteries are more charged than they were, but they aren’t necessarily fully charged. In other words, if the multi-stage charger is turned off before the batteries are fully charged, the batteries will gradually settle down to their own internal voltage, whatever it is at that point. It might be 12.4 volts or 12.6 volts — who knows! Obviously, it should be a higher voltage than when the multi-stage charger first started charging the batteries.

For most mutli-stage chargers, when they resume charging the batteries, they begin the process all over again, first going through the Bulk stage, and then the Absorb stage, and then the Float stage. But again, different manufacturers and different products handle this scenario various ways.


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Most multi-stage chargers have a fourth charging stage which is intended to help wet cell (flooded) batteries last longer. This stage is not needed or used by Gel or AGM batteries. In the “equalize” stage, the charger raises the batteries to an even higher voltage than the Bulk or Absorb voltage for a few hours (generally in the mid-15 volt to low 16 volt range). During this time the battery acid (electrolyte) inside the battery will heat up and begin to boil, sloughing the sulfation off the metal plates in the battery and letting it drop down to the bottom of the battery underneath the plates.

Outback MX60 Solar Charge Controller in Equalization Stage

Here, our Outback solar charge controller has held the batteries at 15.8 volts for 47 minutes during an Equalize stage. At this moment it required 17.4 amps to keep the batteries at 15.8 volts.



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Converters and inverter/chargers on RVs and boats that are plugged into shore power all the time charge the batteries 24/7 and never stop. The way that multi-stage chargers manage their Float stage is one of the big differences between them.

Some chargers keep the batteries at a Float voltage all the time, forever, until they are turned off. Some periodically “reboot” automatically and go back through the Bulk and Absorb stages. A few provide you with a way to force the charger back into the Bulk stage to start the charging process over again manually if you need to.

Periodically leaving the Float stage and going into Bulk and Absorb will help prolong the battery ilfe.



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Generally, the Bulk voltage and the Absorb voltage are the same value, or very close, so the only difference between the Bulk stage and the Absorb stage is how much current the batteries are receiving.

In Bulk, the charger is delivering its maximum amount of current to the batteries to raise them up to the Bulk voltage. A small charger’s maximum current will be less than a large charger’s maximum current is, so a small charger will get the battery up to the Bulk voltage more slowly than a big one will. Either way, the chargers are working at their peak in the Bulk stage, pouring as much current into the batteries as possible.

In Absorb, the goal is to keep the batteries fixed at the Absorb voltage, so the batteries are given only enough current to keep them there. The amount of current they need to do this drops off over time.

So, in the first case the batteries are ramping up to the Bulk voltage due to receiving as much current as the charger can deliver, while in the second case the current going to the batteries is steadily decreasing because they are being given only enough current to keep them at the Absorb voltage.


These are the basic concepts involved in charging RV and marine battery banks. I’ve mentioned a few times how manufacturers and charging systems vary, and in the following posts I will be showing what those variations are.

To continue to the next article in this series, click here:

RV Converters, Inverters and Engine Alternators

Here are links to the each article in this four part series:

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Solar Tutorial Part IV – Solar Panel Selection and Wiring

<- Solar Tutorial Part III – Full-timer Kits                                                         Solar Tutorial Part V – Battery & Inverter Selection ->

The two sample systems described in Part III of our Solar Power Tutorial series are essentially the same systems we have installed on our RV and sailboat.  The RV system is pretty standard for full-time RVers (four 120-140 watt 12-volt panels and 440 amp-hour battery bank).  The sailboat system is bigger than many cruisers carry (three 185 watt 24-volt panels and 710 amp-hour battery bank).

Cruisers often install less solar power and rely on additional charging methods via engine alternator, and wind/gas/diesel generators.  However, we have found our solar power alone is sufficient to live an ordinary house-like lifestyle on our boat (if we don’t use our standalone DC freezer).  We lived for 10 mid-winter weeks in southern Mexico on solar power alone, without using the alternator once (it was broken), and still used two laptops, the TV/DVD, stereo, microwave, chartplotter, autopilot, anchor windlass and vacuum as much as we wanted.

Our rationale for having enough solar power to live comfortably without alternative charging methods was:  we didn’t want to store a lot of gasoline to power a gas generator; we had found that boats with wind generators often suffered from the whirring noise and vibration; and we didn’t want the added cost, installation work and maintenance of an inboard diesel generator.  Solar power has been a great solution for us on both the boat and the fifth wheel.

Part III described these two basic full-timer systems with just a cursory comparison of the solar panel choices.  This page goes into more detail about the various options for sizing solar panels and suggests different ways to wire them.

Wiring in Series versus in Parallel and Wire Gauge Size

There are quite a few choices for solar panel configurations, each with its own pros and cons.  But before choosing a panel configuration it’s worthwhile to consider how to deal with the large current that will be flowing through the wires.  As much as 35 amps or more might be flowing from the panels to the charge controller and then from the charge controller into the batteries.  This requires heavier gauge wire which is more difficult to work with and is expensive.  However, there are several ways to reduce the amount of current in the wires.

If the panels are wired in parallel, the amps produced by each panel are additive while the volts remain constant (Ohm’s law).  Therefore, the cable leading from the connection point of all the panels to the charge controller and then on to the batteries will carry the full current load, or potentially as much as 35 or 40 amps at 12 volts DC.  Heavier gauge wire must be installed to handle this large current load throughout the system.

If there is too much current on a cable, then it will get warm (or hot), and lose some of its precious amperage to heat.  In other words, if the wire gauge is too small, not all the power produced by the panels will make it to the batteries.  It will dissipate as heat loss along the way.  And at the extreme, there’s the risk of melting the shielding off the cable (highly unlikely).

Larger wire is more expensive and is more difficult to handle because it is stiffer.  “Larger” generally means 6 or 8 gauge wire and “smaller” is generally 10 gauge.  The size is dependent on the current flowing through the wire and the length of the wiring run.  A detailed chart for selecting wire gauge is given here.  Note that some charge controllers can’t accommodate wire heavier than 4 or 6 gauge.

If the panels are wired in series, the amps produced by each panel stay constant while the voltage is additive (also Ohm’s law).  Therefore, the cable leading from the connection point of the panels to the charge controller will carry just the amperage produced by a single panel (7-9 amps) at 48 volts DC (if four 12 volt panels are installed in series), rather than the 25-35 amps at 12 volts DC that would flow when wired in parallel.  Because there is less current, thinner gauge wire can be used throughout the system.

In practical terms, most solar power systems on RVs and boats never reach their full potential current load.  During the morning hours, before the sun gets high and powerful in the sky, the batteries get quite a bit of charge.  Usually, by the time the sun is really cranking out maximum energy at noon — the time when the system could be producing max amps — the batteries have already gotten pretty well charged and are starting to ask for less and less current.  So the charge controller has already begun to throttle the panels back a bit and less current is flowing through the system.

Also, solar panels are rated for operating with the sun perpendicular to their surface, and anything other than a perpendicular orientation reduces their output significantly.  In all months except May-July, the sun doesn’t ride all that high in the sky.  We have rarely seen much more than 25-30 amps on either of our full-timer systems, although they are capable of 30 and 36 amps respectively.

Another important consideration is that when a small fraction of a solar panel is shaded — as little as a 4 square inch area on a 2′ x 5′ panel — the entire panel stops producing power.  That is because internally the panel is “wired” in series.  When there is resistance, caused by shade, in just one portion of it the panel’s internal circuitry, current can’t flow through any of it.

By extension, if the panels are all wired in series, when one panel shuts down due to a palm-sized bit of shade, then the entire array of panels shuts down.  A tree branch or part of a boat’s standing rigging or mast/boom can cause the entire array to shut down if it is wired in series.

marine solar panels on hunter 44ds sailboat

Shade from the mast and shrouds on our three 185 watt panels.

If the panels are all wired in parallel, a small amount of shade on one panel will only shut down that individual panel.  Current will still flow through the rest of the panels and then through the rest of the system.

We were persuaded by our solar panel vendor to wire our trailer’s panels in series so we could use small gauge wire throughout the system.  We have experimented with shading a small corner of one of the four panels and were stunned to see the entire array quit working!  However, almost everywhere we boondock we are in full sun.  So, in the end, it doesn’t matter for us. Wiring our RV’s solar panels in series has worked out just fine.   If, however, you anticipate camping under trees on a regular basis and you want to maximize the panels’ chances of getting access to the sun, wire the panels in parallel and use heavier gauge wire.

On a boat, this series versus parallel decision is much more critical than on the roof of an RV.  The mast, boom and shrouds often shade portions of the panels as the boat swings at anchor.  Under sail the shading can be even worse.  So the best wiring option on a boat is to wire the panels in parallel.  However, the cable runs in a boat can be much longer than in a comparably sized RV.  On our sailboat the wiring running from one end of the system to the other — panels-controller-batteries — is 45′.  Why so long?  The panels are high in the air on an arch at the back end of the boat, the batteries are at the bottom of the hull in the middle of the boat, and the all the wiring is routed so as not to be seen.

12 volt versus 24 volt panels

Another way to tackle this issue of having a lot of current flowing through the system is to use 24 volt solar panels instead of 12 volt panels.  When the voltage is doubled like this (24 versus 12 volts), the current is halved.  So the current produced by 24 volt panels is half that of equivalent wattage 12 volt panels (the watts don’t change whether the panels are 12 volts or 24 volts).  We chose to go this route on our sailboat, using three 185 watt 24 volt panels wired in parallel.

Since the batteries are 12 volt batteries, the input side of the charge controller coming from the solar panels is 24 volts while the output side going to the batteries is 12 volts.  Most large capacity charge controllers allow this kind of configuration.  This means that the current flowing between the panels and the charge controller is half that flowing between the charge controller and the batteries.  So, while the panels may be producing 14 amps at 24 volts, and those 14 amps may be flowing from the panels to the charge controller, the current will double to 28 amps at 12 volts when it flows from the charge controller to the battieries.

While the wiring run between the panels and the charge controller can be smaller gauge (less current flows in that portion of the system), the last wire run between the charge controller and the batteries needs to be as short as possible and wired with heavier gauge wire to accommodate the larger amount of current.

We made the mistake of placing the charge controller 25′ from the batteries at first and using 10 gauge wire (I suspect we didn’t explain our situation to the salesmen at the solar panel store well enough when we asked him for guidelines).  When the panels were running at full power we lost about 10-15% of the power they were producing.  Once we moved the charge controller to within 10′ of the batteries and replaced the 10 gauge wire with 8 gauge wire, we lost just 1.5% of the power between the charge controller and the batteries, which is considered acceptable.

Tilting Brackets

Tilting brackets make a lot of sense on an RV because an RV is parked in a stationary position.  In wintertime it is possible to tilt the panels towards the sun (tilt them about 45 degrees).  Most folks align the panels with the length of the RV and tilt them on their sides.  This means that either the driver side or passenger side of the RV will be situated to face due south and the panels will be tilted in that direction.  In most boondocking locations we find we can orient the rig any way we want to because there is so much space around us.

In experiments one December with RVing neighbors who had tilting brackets, we found that their solar power system produced about 40% more amp-hours throughout the day.  Their system was fully charged and their batteries were floating in the afternoon, while ours never reached the Float stage.  Some of that may have had to do with their batteries being better charged to begin with in the morning (we have no idea if they were or weren’t), but it is a pretty dramatic difference nonetheless.

RV solar panels on fifth wheel trailer

Four 120-130 watt panels on our fifth wheel’s roof

However, to get the advantage of tilting brackets, you have to get on the roof to tilt each panel every time you set up camp, and then remember to return them to their flat position before breaking camp and driving off. 

An alternative is to keep the panels flat in all but the most dire circumstances (a week of cloudy winter days), but have one more panel in your system than necessary.  Or don’t even bother installing tilting brackets at all. The trade-off is a few hundred dollars for an extra panel versus climbing up and down your RV ladder and fussing with the panels, as well as the risk that you might drive off with them raised up (we’ve seen plenty of people do that).

Tilting brackets don’t make much sense on a boat because boats move around so much at anchor.  Ours swings back and forth in a 90 degree arc.  Also, the tilting mechanism for a lot of boats introduces shade across the panels at certain angles.  On a boat, it is best to mount the panels as far from the mast and boom as possible and to focus on keeping the shade off the panels as much as possible by forcing the boom off to one side or the other while at anchor.  A fixed, flat mounting position works best.

 For more information about how to select the best solar panels for your installations, see this article:

Which Solar Panels To Buy – Flexible or Rigid? 12 or 24 volt? Monocrystalline or Polycrystalline?


Most of the components for an RV or marine solar power installation can be purchased at Amazon.

Shown here is a complete full-timer's kit (far left), a big charge controller (middle) and a big inverter (right). More comprehensive listings of each component type can be found at the following links:

Purchases at any of our Amazon links help cover our out-of-pocket costs for operating this site -- thanks!


This is the end of our solar power tutorial series.
We have lots of other info about solar power on this website. See the pages listed below to learn more.

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