Solar power is pretty amazing, especially on the road. The idea that you could have energy generated anywhere? Pretty cool. So when we heard that Kevin’s dad had been gifted a 400 watt solar array from a friend we got very excited. The van is very comfy in general but being able to use basic cooking appliances and recharge our laptops will push it that one extra step into palatial (for a van).
So while we were in Las Vegas for a month, we installed one of the panels! It’s a common theme that we come by resources second hand and have to figure out how to work with what we have rather than buying preset kits or ideal configurations of equipment. So this blog post is for the DIYer that wants to know the nitty gritty of solar installs from the perspective of a total electrical layperson.
Lets dive in!
The basics of any full solar panel system are: Solar panels –> Solar controller –> Battery array –> Inverter. This post is only going to be about the first step of getting your solar panels secured safely on the roof of a vehicle and getting your wires in place. The rest of the steps will be detailed in part 2.
Here are the solar panels, each one is 100 watts and there are two panels per mount. That makes a total of 400 watts of solar panels if we mounted both. I thought about doing that but in the end decided not to. For now we’re just mounting one to test the system and we’ll likely add the second one at a later date. When we do add the second we’ll have a joining box up on the roof and rewire the entire system so we can re-use the electrical cables that have to pass from the roof into the body of the van. I definitely don’t want to break the seal on the giant hole we drilled in the roof. But I’m getting ahead of myself!
Step 1 was to attach the mounting brackets to the solar panel and get it up on the roof to measure where the brackets should be drilled in. I chose to set it about halfway back along the van so that our sun roof wasn’t blocked and the wind coming off the windshield wouldn’t catch under the edge of the solar panel to compromise the brackets.
Once we had the placement right, I marked the drill spots on the roof with a sharpie and we took the panel off. It’s important whenever you drill big holes in your roof to seal it VERY well so you don’t get rain and debris in the raw metal edges, this can rust and corrode the metal and give you leaks, rot, and other problems. So when we went to set the mounting brackets in the roof we used a self-leveling roof sealant that we got from Camping World. We would drill the holes at the markers, glob sealant over the entire area, then place the mounting brackets and screw it down.
The sealant takes a while to dry (although it remains soft and pliable for a while) so we left it and came back to the install the next day. It was time for the scariest part, drilling the cable access hole. Buying the right cables for your system is very important since having a cable that is too small to handle the amount of electricity flowing through it at best will reduce your system’s efficiency and at worst could cause a short or even an electrical fire. Because our hand-me-down solar panels and solar controllers didn’t come with the original tags or manuals, I had to do some sleuthing to find the full system ratings and get information on what kinds of cables we needed. Scraps from the previous system wiring showed that they were using 8 and 6 gauge cables (the smaller the number, the thicker the cable). I knew our panels were outputting at maximum 200 watts and 12 volts. I needed to know the amps to get the right cable type so it was simple math: WATTS = VOLTS x AMPS. So we needed a wire that could handle 16 amps. BUT I would want to add a second set of panels later which would increase the system to 400 watts so that meant the system would eventually need 33 amps. So I bought 8 gauge cables to use on the solar array (always round up for electrical systems).
Here is a handy graphic from Sonic Electronix showing what the cable ratings are:
So now we have our cable gauge right and we can drill the giant mucking hole in the roof (wheeeeeeeee……..). It was terrifying and our drill bit wasn’t happy but we got it done! As a bonus, the terminus of the hole was behind an interior window valance in the van so it ended up being a lot prettier than I thought it would be. I wish I could say that I planned that.
So now we could thread the wiring through the hole and seal it into place. Getting a good seal around the wire was going to be crucial if we didn’t want rain getting in. Sealing a hole the size of a quarter is pretty nerve wracking. The van interior has an insulated gap between the outer roof and the inner ceiling so we had to plug a space of about a half inch. We dithered around in Home Depot for a bit looking for something to fill it in with no success. Then as we came home dejected, our music gear came to the rescue. Cymbal felts were perfect! These little fuzzy discs would fit over the cable and poke down into the hole perfectly and should be able to absorb any excess moisture if it got in through an imperfect seal. We covered the top of the hole with roof sealant tape and topped the whole thing off with a ton of self leveling sealant goo.
Then it was time for the final mount! We placed the solar panels on the now fully solid mounting brackets and bolted them in. Solar install complete! I decided to delay in finishing the wiring since our battery system hadn’t arrived yet. The rest of the install including wiring and interior components like the solar controller, batteries, and inverter will be detailed in part two! I hope this was helpful and informative for anyone looking at installing a solar panel system on their house or vehicle. It took a decent amount of research to accomplish but I know it’ll be worth it! Leave any questions in the comments and I’ll answer them.
For the Pinterest Happy: