Sometime before COVID came in, we decided to remodel our home, and in the process ended up upgrading our solar panels. This left me with a pile of 230W Sunpower solar panels with no proper home. I gave a few to my Dad for his RV, kept a pair of them for myself and sold the rest on Facebook. My plan was to mount them on top my Jayco Featherlite camper, to provide a little extra power while camping (play the tunes, keep the lights on) and to keep my battery healthy while it is in storage. Solar power systems are actually pretty easy to self install, if you feel confident with a drill, screw driver, and working carefully around some relatively high DC voltages.
Prior to getting started I did some online research about what would be needed, pulled out the measuring tape, and started making some purchases on Amazon:
Solar Panels — 2x 230W / 45V — $150
Already had these, you can find some really reasonable panels for cheap online. Locally, I can still see a number of 200+ Watt panels for around $75 each. What to look for here is the dimensions (make sure they can fit on the empty space on your trailer roof), the voltage (easier if they have the same output voltage) and the wattage (consider wattage per square foot, since there is limited real estate). The two panels I purchased max out at around 450W realistically. But remember, this is just peak output, full direct sunshine. Honestly, this is plenty for my needs.
Solar Charge Controller — Victron 100/30 — $260
The solar charge controller is the “brains” of your operation, it takes the high voltage from your panels, and funnels it into your battery storage system, it decides when to cut off the batteries (to prevent overvoltage / overheat). There are cheaper controllers out there, but I heard really good things about Victron. Compact, really solid, and for my buck, the best app control / configuration. The Victron has cheap battery monitors that you glue to the side of your battery that keep track of individual battery voltage as well as temperature to keep the battery at a safe temperature, preserving it’s longevity (more about this later). What to look for here is max voltage, and max amperage. With Victron, this is easy as it’s part of the model name (100V / 30W) — I chose the 100V max voltage unit so that I could hook my two panels in series (which causes the voltage to be additive) I could have hooked them up in parallel, which would keep the voltage the same, but would have required a little more wiring / plugs. 30W is more than enough, you normally want to overshoot max wattage by 20% or more, but at 5W a panel, I’m good even if I want to some day add a bunch more.
Cabling / Mounting System
I measured the length of cord I would need with a tape measure, plotting where I would be putting my cord through the roof, running it down, and where I would put the controller. You need good thick cable to have low loss DC, and not worry about overheating. Also, weatherproof or outdoor cable is useful for the roof section. I went with 30' of 10AWG that also had the right kind of SAE connectors on it to make it easy to plug in to my panels. For mounting, I luckily had the leftover extruded aluminum rails from my existing system. These ended up being really solid, and I can’t stress enough how important that is for being able to drive down the highway at 60+ MPH with solar sails on your roof. For water proofing my roof I purchased white Flex Seal tape, and Flex Seal Spray. Also, to make hooking everything up I bought some O-Ring wire terminators, and some terminals for connecting power to.
Overall probably took me 3–4 hours to install the panels, as this was the first time I’d done anything like it.
First step for me was to drill my roof holes, mount my installation brackets, and run the power cable through the camper. I picked a spot for my panels, laid out where I wanted my rails to go and then plotted where to put the mounting “brackets”.
Best way to secure your panels depends on your roof type, and for mine (rotted plywood), this seemed like the best way to secure them. If you can find studs, or drill into aluminum framing that may be even better.
I also angled the rails so they were lower in front and higher in back to create a bit of an “airfoil” to hopefully keep them together.
For the cabling I drilled 2 holes in my roof right above where we have a floor to ceiling cabinet, ran the cable down the back of that cabinet, underneath a sofa (alongside some heater ducts) and into the storage area at the front of the RV near the battery and power systems. I think if I had to do it again, I would have used a nice junction box rather than rough circles where the cable went into the camper, but this will probably do. I held it in place in a couple of places using an insulated staple gun that I’ve got for mounting cables to things that I use whenever I get the chance.
Hook up solar controller
Be careful when hooking up your solar controller, hook up Battery (negative first) and then PV (Solar lines, ideally before connecting them to panels) and make sure that the terminals match up correctly (Victron had positive on outside and negative terminal on inside) as a screw up here could cause your nice controller to melt and the magic smoke to get out (don’t ask me how I know)
You should also get as smart battery sense for each of your batteries (I just have one, but may end up buying more) this bluetooth networks to your victron controller to provide charge and temperature information and will greatly increase the life of your batteries.
With this all hooked up, you can plug in your solar panels, and configure your victron (from iOS App), add your smart sense to a virtual network with your controller and you are generating power! (Screenshot came from after sun was mostly down, but was producing 350W when sun was higher)
Final Mount Down
Last, I went and bolted the solar panels into the rails, zip tied off the cable to keep it from bouncing around, sprayed flex seal on all the bolts that I ran through my roof and on the little holes that were opened for my power wires to keep the roof airtight, put flex tape over any cables that were exposed to the sun, and cleaned up / vacuumed the job.
For the brackets, I spaced them so there would be 2 rails on which both panels would sit, and 3 brackets per rail. I drilled a 1/2" hole for each bracket all the way through my roof, and then put a 1/2" bolt through the roof capping it with a washer and nut on the inside of the camper. This is a little ugly, but my roof seems to be on the thinner side and I wanted something really sturdy.