Adding Solar Power to Our RV – Rig – Travel Trailer

Exterior of system

Like many campgrounds we have stayed at, our current home base for April 2014 in Osoyoos BC charges extra for electricity if you are a long term (one month or more) resident. We had been in this campground of over 400 sites for a week and half and we popped into the office to get the stats on our power consumption. The nice fellow at the office checked his computer for us.

“Wow!” he said, “you’ve only used $13. Everyone else is averaging $35-45 and I have one guy here at $89 but you’re only at $13.”

“We supplement with solar,” I replied.

“You sure do,” he said. This launched into a discussion of solar and RVs which prompted me to share our experience with our rig’s custom designed solar system.

When we first began looking into adding solar to our RV we started by making inquiries about who had already succeeded. We were almost uniformly greeted with stunned looks and comments like “but you can just get an electric site or use a generator, so why bother?”

Things have really changed since those days. A lot of RVs come equipped with solar panels as standard or additional luxury add ons. I have also heard advertising of newer rigs that states they have “solar wiring preinstalled” and “space for addition of solar panels”. Still, based on our experience and what I am reading, the solar energy industry has not yet caught up with the potential for RVers. Solar is now practically required for dedicated boon dockers.

First though, let’s begin by addressing a few misconceptions we encounter all the time. Solar panels are indeed a wonderful thing and yes, the sun is free. However, a solar panel is not like a generator you can turn on and assume it will be putting out a certain amount of power. It may seem obvious to say this but we have found it needs to be said. Solar panels don’t work without sunshine. We have found that if you have a long cloudy stretch, like the ones that occur on the west coast of Oregon, solar does not work reliably. Also trees take up lots of sunshine very effectively so your panels aren’t going to work in the shade either. I have never managed winter camping in Manitoba, but I suspect the short daylight hours of December would also be highly problematic for solar. (Update note: We have continued to use our solar panels while our trailer is parked by our house in late fall in Manitoba and indeed, the solar array cannot manage to even run a radio in late fall when the days are very short and there are cloudy stretches or snow and ice.)

Second, solar panels don’t put out a lot of power. Many of my greenie friends who mean well but have never actually worked with solar themselves have no idea how little power solar panels put out even with the sun shinning. They have some vague feel-good idea that solar is cheap and good for the environment and so if you throw a couple of panels on your rooftop, you can avoid putting money in the hands of evil big oil. This is simply not true. Solar is limited by physics.

Think of it this way. A tree collects solar energy one photon at a time using specialized collecting systems within the leaf. By covering the entire structure of the tree with many little green collectors, the tree takes in a lot of power for growth, one photon at a time. When plants die and are turned into coal and oil, all that hard work the trees and the other plants did is distilled down and concentrated. Solar power’s energy is not unlike a light beer compared to 200 proof white lightening that comes from nuclear, hydro or coal. If you want as much power as the typical land connected RV unit uses in electricity, you will have to add so many collectors and batteries, you won’t be able to move your rig because of the extra weight. (I just can see all those who use solar are saying ‘but’, ‘but’, ‘but,’ right now. I am getting to that.)

Notice that caveat. “If you want as much power as the typical land connected RV unit uses in electricity…..” We are not just an energy hungry society. We are an energy greedy gluttonous society. We are spoiled rotten brats when it comes to power consumption. We think absolutely nothing of upping our power consumption by huge amounts just for the tiniest increase in convenience.

The best example of this gluttony is the lowly tea kettle. If I want to heat a cup of water to make a cup of tea, I can do it in any number of ways. I can put a kettle on the stove. I can use the microwave, or I can use an electric kettle. When I first started being concerned about solar I became aware of the watt. The watt is a lovely little indicator unit that, if you understand it, tells you about the conversion rate of something into to some other form of power. In the tea kettle, the conversion is power of electricity to heat in order to boil the water. When I first realized it was my tea kettle that was blowing a breaker in my trailer I checked and my tea kettle used 1000 watts. I set out to find lower wattage tea kettle. I was astounded to find that over the years electric tea kettle manufacturers have consistently upped the wattage of electric tea kettles. I can assure you it is almost impossible to find a lower watt tea kettle. When I first began looking at watts most tea kettles were 1000 watts. Now they are all 1500 watts and I have seen more than a few 1750, 2000 and 2500 watt ones. Point of origin heaters, like the ones that delivery instant hot water typically draw 5000 watts. (I’ll grant you the point of origin heaters use less energy overall because they only heat what is actually used instead of keeping a large hot water heater always full, but only if you have the upfront watts.)

It doesn’t matter that a 1500 watt tea kettle uses a lot more electricity for a shorter stretch of time. It heats water to a boil in fewer minutes and therefore, as far as the average consumer is concerned, the higher wattage, the better the kettle. Now I suppose one can justifiably argue that if you have two tea kettles with an equal volume of water, but two different wattages, the amount of work required to bring them to a boil is the same. It doesn’t matter whether you can do it in a few minutes with a 1500 watt kettle or in several more minutes with a 600 watt kettle. The same amount of power has to go in. However in my trailer, using a 1500 watt tea kettle means my breakers break if I plug in anything else and my solar converter, the device that takes sun energy and changes it to electricity, just can’t keep up. My solar system can put out a maximum of 600 watts at even given time. My current system can handle the 600 watt tea kettle without a problem if the morning sun is out. I would need a lot more solar panels to make enough power output for using a 1500 watt tea kettle. I suspect for the power companies of the world, this consumer switch to ever higher wattages for a few minutes less waiting for our boiling water is a good part of what fuels our societies constantly increasing need for more and more electricity. Maybe, if everyone just decided they could wait for an extra few minutes for a 600 watt tea kettle to boil their water, we could avoid damming a few more rivers. Yet, how many people check the wattage required for the new tea kettle? The best way to discover how ready a person is to use solar is to ask them what is the wattage on their tea kettle. If they don’t know (and most don’t), they are rank amateurs, as I used to be.

When we first started checking on solar we had a near universal experience at every solar panel place we went into. Some bright eyed young fellow who had never used solar himself, would take out a calculation sheet and begin.

“How many TVs do you have?”

This would be followed by taking an inventory of all our electrical appliances followed by some calculations and then the pronouncement.

“You need 12 of our megapanels and 14 of our supermega batteries and the cost will be half the value of the cost of your entire rig. We can come and install it next Tuesday sign here and give me a cheque for 25% down.” (At least that is what I would translate it to.)

“We live in a travel trailer. How do we install it on our travel trailer?”

“I have no idea. You’ll have to check with your manufacturer or get a certified RV technician to install it.”

Which brings me to the next problem we had. Our manufacturer had no idea how we could do it and we were not able to find any RV certified technicians who knew anything about solar. They were all for sending us to see the guys in the solar places.

“And how much does this system weigh?” I would ask next. “Our trailer can only support so much additional weight.”

Our salesman would invariably blink and swallow a couple of times and then say something like “Well,… batteries are heavy.”

After a few false starts, and a lot of self education, we decided to approach the problem in an entirely different manner and it worked for us. The typical recreational rig has two power systems, one 12 volt and one alternating current. The essential items like the fridge and hot water heater also have dual modes, propane and electric. Lights can run on both regular battery and the land line electricity. Most of the things you would want connected to your solar panel power supply are those which can only run when you are connected to the land line via the electrical cord. This usually means the television, kitchen appliances, electric stuff like hair dryers, and computers and the chargers for cell phones.

We quickly decided what we really needed was a back up power system for our security system so it would work even when we were traveling. As it was, while traveling we had to keep the system on by using two nine volt batteries that were designed to be a back up if the power failed. We were going through a lot of those batteries and we often forgot to check them and keep fresh batteries on hand reducing the effectiveness of our alarm system. A working alarm system without a land line and without 9 volt batteries was the first priority.

We also started looking at the watts demanded by assorted electric appliances. It is a fact that making heat requires a lot of electricity. Therefore, while on solar only, we would cook with propane instead. We added a second regular battery to our standard 12 volt system to give us lots of power for lights and such while not on the grid. We made a considered decision to not run the air conditioner. We simply don’t use it enough while summering in Manitoba to justify the extremely high cost of enough solar to provide air conditioning. If it ever gets that hot we’ll relocate to a place with power and plug in until the heat wave passes. Last, but not least, we invested in a small Yamaha generator for cloudy days. That was probably a total waste because we have only used it once but it worked very well that one time. I am glad we decided to skip the air conditioning because that would have meant purchasing two Yamaha units. So with a clear idea of our energy needs priorities and a willingness to put up with inconveniences like the tea kettle taking several minute to boil instead of one minute,  we were now in the correct frame of mind to go ahead.

With those specific and limited power needs clearly outlined, we then decided to see just how much solar we could support given weight and roof space restrictions. and if it would be enough to make up the difference we wanted for the real power needs. Those two considerations with a trailer are something you just don’t have with the stick house. I spent some time up on the roof measuring open space and we assessed various options for storing batteries. We considered and rejected portable solar panels that could be put outside somewhere and connected to the trailer for three reasons. One, we are lazy and don’t want the work. Two, such systems too easily get up and walk away on their own. Three none were big enough for our needs. We eventually determined we could take four 140 watt solar panels and four golf cart type batteries that were of the absorbent glass mat type or AMG. The battery storage we designated in the space over the axles and under a bench where the heavy outdoor slide-out barbecue we never use was sitting. We removed the slide out barbecue and it matched the weight one battery. We used the access door to the barbecue for access to the inverter and to provide ventilation from the batteries to the outside. (Update: In the end our battery choice of AGM was wrong for our needs and we do not recommend this type of battery for an RV. See our note below about our replacement.)

To spread out the cost and take advantage of lower US prices we did the installation in two steps. We installed the solar panels first and declared those on one trip. We purchased the batteries on a second trip. Doing it this way meant we could come in duty free. We bought the solar panels from a company that had excellent support and the fellow we dealt with provided us with installation instructions and detailed diagrams. He also took care of calculating the assorted thicknesses required for wiring between batteries, panels, charge controller and from roof to interior. He also selected the special fuses we would need in two places and selected the main on off switch. Our solar panels needed to be installed above the roof with an inch and a half of air space for heat dissipation via air circulation. (Some of the newer kinds don’t have that requirement.) The solar system supplier found yet another RV supplier who had a brace system which would allow us to mount the solar panels with the required air space and that provided us the option of tilting the panels when we were stationary or having them flat when we were traveling. The braces required we install eight long thin metal strips with four screws directly into the roof for each brace. No one could tell us how to do that best, so we had to research it ourselves.

Drilling holes into the rubber roof of the trailer was the second scariest part of installing solar. If not done properly, the result is a leaking roof that cause endless troubles we didn’t want. I carefully researched everything I could find on attaching assorted things to the roof as the pros do it. The principal is always the same. Drill the smallest hole that can do the job. Goop the hole and screw with roof sealing material, slap something on over the hole and screw in place. Seal the whole mess again, screw, cover, bolt and nut. Inspect frequently and reseal as required. We then researched how our trailer was built in order to determine what part of the roof could best handle the weight and pull of whatever fastener we chose to use. In our case, there was the rubber layer, a black underlay, a layer of plywood, an inch of white insulation material and then the interior layer which the ceiling tiles were fastened to. The plywood was the best part to fasten to. The next step was to decide on the kind of fastener to attach the braces with. After some consideration and a lot of time examining bolt types we chose special half inch bolts that had a spring loaded popping out device that would open in the inside just under the plywood after being screwed in. They would go in easily but would not come out. Decision made, we were ready to install the brace system to support the solar panel.

That took a lot more planning than doing. Since there was no way to move a screw after it was put in, we put together the solar panels on the braces, I laid the braces with attached panels directly on the roof and marked where each screw would go. Then I did it again and then I checked everything a third time just to be sure. Once the planning stage was complete, the installation went quickly. Drill a small hole. Add generous dabs of good quality sealant. (I used silicon seal for the inside part.) Insert the screw and deploy the expander. Add a flat washer to go over the hole to seal in the silicon. Add a lock washer to keep everything tight. Tighten the bolt until just tight but not enough to bend or warp the roof line. Once one brace is in place, cover all the holes, edges, bolts and such with another layer of sealant, this time using the outdoor sealant specified for use with the rubber roof. Double check that the holes still line up properly at the other end. Install second brace. Repeat. We then waited overnight to make sure everything dried completely. Because I am crazy paranoid about making leaks, the next day I inspected the entire thing yet again and added more seal in a few places, just to be sure. We then mounted the solar panels on the roof brace. We did not connect the wiring right away. The mounting part took two afternoons of work, 2/3 of it planning and measuring and remeasuring.

Solar panels mounted, we now concentrated on the batteries. Because I did the roof portion, my husband handled the batteries. As it happened, our good friend who is also an engineer, came to visit and part of his visit was helping us design the battery box and ventilation system. (Batteries make gas while charging than can explode if not vented.) He also helped us design a wall mount for the breaker box and charge control panel. You must have a charge controller to regulate how much power goes in and out or you will lose about 30% of your potential power and dramatically shorten the life of your batteries. (Update: Letting batteries go flat will also do this and we killed our AGM batteries dramatically reducing their lifespan to three years. Tis is why we recommend not using AGM batteries.) Again we did not hook up the wiring after the batteries and other devices were in. Our friend was an engineer not an electrician. He didn’t want to be around when we started playing with power and we respected that. We just drove the trailer and stayed at another campsite for a weekend to be sure no issues with the weight or location turned up. I’m kind of ashamed to admit it but it took us another four months before we got the nerve up to begin the actual wiring. Electricity is a scary thing and one of our sons is an apprentice electrician and he made sure to scare the pants off us about what could go wrong. So we waited before starting the connections.


First, I connected the solar panels to the power system controller box. This intermediate between the batteries and the solar panels is needed for a bunch of reasons but mainly for keeping the batteries from overcharging and increase efficiency of charging. This required running wires from each solar panel. I started with a wiring diagram from the company that sold us the panels. I put the ground wires in first. That gave me practice attaching stuff. Learning to use the crimping device and the connectors turned out to be a high cuss job so I was pleased I learned that on the grounding system first. Also, even unconnected those panels get mighty hot so I always made sure they were covered with a heavy quilt as I worked just to make sure I didn’t burn or electrocute myself. I wired everything except for the last step of closing the loop to let the power flow. I drew a diagram of everything. We sent our own diagram of what we had done back to the solar company for approval. They sent us back a message saying it all looked right. I had my son come and take a look. He protested a lot saying he was not certified and couldn’t really tell us right or wrong but, because he loves his mother, he did eventually say he saw nothing wrong with the advice we had been given by the solar company and he approved of the way I had connected things. He also fretted about local code compliance. Concerned about coding and legal issues and insurance, I contacted a full electrician. His answer kind of surprised me. The trailer modifications we were doing fall under motor vehicle regulations as far as electrical work went. There was nothing wrong with someone doing their own wiring on a vehicle. Also, he had never done any solar work and couldn’t really advise us, but it sounded like we were doing it right because we were working with people who were supporting their product. Eventually, I did get up the nerve to do the final hook up and the charge controlled purred happily sending us all the right signals. No explosions, no fire, no shock. Whew! The controller box had a very nice digital type display that was really hard to understand and took two more phone calls to the support people to program correctly.

Connecting the batteries didn’t go quite as smoothly. We used the same procedure again. We hooked up just about everything but did not do the final step. Our system included a huge copper fuse. While arranging stuff for bolting into the frame, my husband had one thing touch another and there was a huge pop, sparks and the fuse melted exactly as it was supposed to. The plywood box had nice crispy burn mark on it. We had to go to a store for electricians and purchase a new fuse by special order before proceeding further. The lesson of that misadventure is when you are wiring things up, wire the fuses in first. We did that entirely by accident and I don’t like considering what might have happened if we hadn’t done it that way. Again, we did our own diagram and sent it back to the supplier, and again, they sent back their approval. We laughed about blowing that copper fuse. They didn’t laugh. After we hung up, with heart pounding, we made the final connection. Nothing happened this time except that the charge controlling thing started producing proper numbers as per the manual. We had our solar panels and they were charging the batteries and all was well.

The final step was to create three sets of plugs to access the solar power at strategic locations in the trailer and hook that wiring to the inverter. We decided to use a 600 watt inverter for two reasons. The 600 watts were dictated by the 600 watt tea kettle since I can’t function without my morning coffee. Also, I found a top of the line 600 watt inverter at a garage sale, still new in its box, for a mere $25. This was the best type of inverter you can get with built in controls so that delicate electronics are not subject to fluctuations in power supply that can make them sick. $25 is a lot less money than buying such a thing new. The fellow who sold it to me didn’t want to discuss why he was getting rid of it. Maybe he didn’t connect the fuses first. We later added a battery bug to give us a fast and easy update on percentage of power in the batteries. There is a way to do it with our fancy charge control thingie but I hate doing math when a simple device can give me a straight percentage. My husband also came up with a system whereby we can use our solar panels to run a trickle charger to recharge our two regular batteries should we need to. So far, we have not needed to do that.

(Update: I did eventually learn how to read what our charge control thingie without doing a stupid conversion or using the battery bug. If the “power” line that is the lower of the two is in the upper left says 13 or higher, it’s fine. If it says anything below 13, we are too low and potentially damaging the AMG batteries. The AGM batteries dropped to 12.7-12.3 several times before I learned this which is why they only worked reliably for three years and were complete toast by five years. Since we switched to the big marine/deep cycle I have seen that number drop to 5 before output stopped and the battery has recovered just fine. I don’t recommend doing that on a regular basis but life happens.)

How has is worked out? Surprisingly well. On a day with full sun (after I have had my morning coffee) we can run all the computers we have. I have a MacPro laptop, hubby dearest has iMac with an auxiliary disk and second screen. We can keep our two cell phones charged and charge the MIFI station that keeps us connected to the world when we don’t have WIFI. We also have a small battery backup added to my husband’s system so a power failure doesn’t shut the computer down without a five minute warning. With this he can do an organized save and shut down. Our entire alarm system also runs on the solar and that part works like magic when we travel. We have found that if it is cloudy, we have to move the computers back onto the external grid system. A long cloudy spell on the coast and we have to remove everything but the alarm system. A shady site for more than a day means no solar at all, even the alarm. The limitation on the system is sunlight. It does what it is designed to do as long as there is sun. No sun, no power.

Would I recommend it to others? Yes, I would recommend adding solar with a few caveats. First you will need to thoroughly research this for yourself. I have noticed more and more professionals who seem to be acquiring the knowledge neccessary to properly install a solar system on an RVer’s rig. However, you will at minimum need to know enough to find one and make sure this person is for real. You will also need a really good supplier who is willing to work with you providing real support by people who know what they are doing. (Our supplier was Wholesale Solar located in Mount Shasta California and I can’t say enough good things about them! What a great bunch of folks they are!) Check local regulations to make sure you aren’t violating any laws. Double, triple, and quadruple check everything before you commit to the final step of drilling holes or hooking up power. This is not a job you can just kludge.

Are we saving money? The whole system cost us $3800. At $40/month average savings at places that charge extra for power, the system would need to be in place for 8 years of camping where we have to pay extra for power to pay for itself. Given lots of places don’t charge extra for power and the lifetime of a trailer is usually about 10 years, it probably won’t pay for itself by working as a supplement alone. This means we would have to do a lot of boondocking, taking no power sites at parks that offer dramatically lower fees, and doing things of that nature to make really dramatic savings. Otherwise, we just can’t hope to recoup those upfront costs. We really don’t want to work that hard so it’s not happening. It is so much easier to plug into an electric site. Solar panels and solar systems are improving dramatically and upfront costs are dropping, so the tipping point into profit is coming sooner and sooner. Installation is also getting easier and weights are dropping too, now that the newer flexible panels have become available. When we need to do it again on our next rig, we will likely be able to have more power for less money and need less roof space. Or so I keep hearing though I have yet to see any actual evidence this is true.

We use our solar at almost every place we stay at on environmental principal alone whether or not they charge for electricity. Most American campsites get their power from things like coal, so the less we use the better for the Earth. In Canada, power is largely hydro, but what is not used by us, is sold to the USA. We also boondock and use no electricity sites whenever we can. I also take great comfort in having our alarm system working at all times. There have also been a few times when something went wrong at a campsite and we lost land line power for a few hours. We are barely affected by such an event. Finally, I really appreciate the freedom that comes with the ability to go anywhere and still have all the power we need, (although not all we might want). For us, the solar system has most definitely worth it.



About tumbleweedstumbling

I have three blogs, embryogenesis explained, tumbleweed tumbling AND fulltimetumbleweed. I am a scientist, and my husband and I have written a book which was published by World Scientific Publishing in Nov 2016 called Embryogensis Explained. Full time tumbleweed was my first blog which I worked on during five years of living full time in a travel trailer. I have now retired that blog in favour of Tumbleweeds Tumbling since we bought a stick house in April 2015 and are no longer full-time. I have a blended family of five sons and one daughter, all grown up now. I am (step)grandmother to nine boys and one girl. My husband and I have a dog and a cat. We spend summers in Manitoba, Canada, in a 480 square foot house on a half acre of land in the tiny town of Alonsa. We spend winters in the USA. My husband is retired and being a US citizen, he does volunteer work in winters for Gulf Specimen Marine Lab in Panacea Florida as their emeritus. I retired in Sept 2013 and so far I am loving it.
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2 Responses to Adding Solar Power to Our RV – Rig – Travel Trailer

  1. Update: The batteries lasted for precisely the five years they were said to last. We can still use the set up to run a computer if we are in full sun but otherwise we have no storage. We went shopping for replacement batteries. After looking at multiple options we went with a extra large size heavy duty deep cycle/marine type battery. This battery puts out as much power as our four original batteries. Because it is deep cycle it isn’t damaged by being flattened the way our previous batteries were. The thing is heavy but the weight is still less than half the weight of the original four batteries we installed. This one battery was 1/3 the price.

  2. Pingback: Ninth Stop: Cherryvale Big Hill Lake, Kansas | Tumbleweeds Tumbling

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