RV Solar Part 2: Installation 4

Part 2 – Installation


As mentioned earlier, UPS damaged one of the panels, so there was a delay while AMSolar shipped another one.


In the meantime, I laid out all of the other components on a table like a big schematic and walked through all of the steps I had ahead of me and checked to see if I thought I had all of the parts I’d need. Of course, there were the inevitable couple of trips to the hardware store, but after going over it a couple of times I was pretty sure I had all the specialized components I’d need. This also gave me a chance to prep some items, like the wire seals and holes that needed to be installed in the combiner box, or the cable clamps in the knockouts on the controller.


When my replacement panel arrived, I was ready to start.


I began by mounting the controller in a compartment close to the batteries and pulling a pair of 4 gauge wires from there to the battery box. I mounted the 50A marine circuit breaker in the battery compartment inline with the positive. I went ahead and connected it to the batteries, but I  left the breaker open so the rest of the cable was disconnected. I also ran the temperature sensor into the battery box and the chassis charge wire to the chassis battery disconnect switch in one of the front compartments, connecting to the battery side of the switch with a 5A fuse.


All of these connections, with the exception of the controller ( which had large screw terminals for bare wire ) required crimped on lug ends of one size or another.


Note – If you’re going to do this yourself, most of what you need are normal hand tools, but if you’re going to be working with wire heavier than 10 gauge, I suggest getting a good pair of cable cutters ( http://www.amazon.com/Greenlee-727-Cable-Cutter-9-1/dp/B001RSMPWU/ref=pd_cp_hi_3 ) and crimpers ( http://www.amazon.com/Klein-J1005-Journeyman-Crimping-Cutting/dp/B000936OTY/ref=sr_1_17 ) .


From the controller compartment, I had to run more 4 gauge cable up to the roof where the panels and the combiner box would be. I chose to run it up along side my black/grey vent pipe at the rear of the RV. This made for a rather long wire run, which is why I chose to use 4 gauge wire for this. If you have a refrigerator vent, I suggest using this route to get the power down from the roof.


I tied the wire along the back frame of the basement storage, going over the suspension on the chassis framem taking care to keep the wire secured with wire ties and up out of any of the points where the suspension would move.


On my RV, there’s a panel on the passenger side of the tank compartment that removes with about a dozen screws, exposing the ends of the tanks and the bottom of the vent pipe that goes up through the roof. With the tank ends exposed, I could see an open spot in the bottom of the compartment to drill a hole to pull the wire up. There was extra space around the floor where the vent went through, so I pulled the wire up through there. I then sealed the floor space around the cable with expanding foam and the bottom of the compartment with silicon sealant and put the cover panel back on.


I tied the wire to the vent pipe with plastic wire ties and ran it up to the ceiling of the RV. On the roof of the RV I removed the vent and cut a large enough hole in the side of the vent for the wire to exit. We replaced the vent ( now with the wire running through the side ) and covered the base and the wire exit liberally with sealant.


With the wire runs done, we took the cardboard that protected the panels during shipping and put them up on the roof to use as templates to figure out where we were going to lay the panels on the roof, as well as how much 10 gauge 2 conductor wire we would need to go from the panels to the combiner box.


With the panel locations penciled on the roof and the wire runs planned, we got back down and prepared the panels. First, we cut the individual runs to length and marked each panel with tape and a sharpie so the right panel ( with the right length of wire ) went into the right position. Then we crimped the wires from the panels to the cable runs and put heat shrink tubing over that to protect them. Finally, we attached the mounts with the included bolts and taped cardboard over the panels so they would not be putting out power while we connected them.


My RV has an aluminum roof, so AMSolar had suggested that the 3M VHB double sided sticky tape was sufficient to hold them in place on the roof without any additional screws and thus additional roof penetration leak points that come with them.


We carefully handed the prepared panels up to the roof and set them in their positions, laying the cables back to the combiner box, with a foot or two to spare. Where the cables ran alongside one another we tied them together with plastic cable ties ties ( use the black ties for UV resistance ) and stuck it to the roof with a cable tie mount.  When we were sure we were happy with the position of the panels and the wiring ( make sure to leave enough extra wire to tilt your panels if you have tilting mounts!), we cleaned the roof well with rubbing alcohol and stuck down the mounts.


Next, we used VHB tape to stick the combiner box to the roof. We then ran each wire into the combiner box, cut it to length, stripped the ends and fastened them to the busbars inside the box. We did the same with the 4 gauge wire going down to the controller through the RV and put the cover on the box.


Then we went back and sealed around all the panel mounts, cable mounts and the combiner box. You want to totally cover the VHB tape to keep sun and rain off of it, to prevent degradation to the adhesive.


We removed the cardboard from the panels and we were done! Unfortunately, it was dark out by this time, so we didn’t have any idea if it worked.


Details on how it came out, what I think I learned from this, and a mostly full component list with pricing in part 3. Here’s a link to part 1 of this series.

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4 thoughts on “RV Solar Part 2: Installation

  • Robin

    I want to read part 1 please?

    Work at a small internet radio station…drawing up plans for solar powered RV to travel to concerts and do remote
    live broadcasts. This article is informative! But the first part would help a lot , I feel.


    • Eric Post author

      Parts 1 and 3 are available from the home page. Thanks for the suggestion, I’ll add links to the other articles into the articles.


  • Salman

    This sounds rellay outdated, but what I would do is look in the local yellow pages under Solar . You could do a web search without leaving your chair, of course, but any fly-by-night can put up an ad for solar. An outfit that has a yellow pages ad is likely to have been there for a few years.Ask them to come to your home and do an evaluation. There should be no cost for this, and you will learn a lot from getting a bid.Solar hot water is usually the first thing to put in, as it has a better payback than electric (although it’s not sexy and high-tech). Yes, it can be installed in places where there are freezing temperatures in Winter, and it will actually heat water on a sunny day in Winter.Solar electric usually does NOT involve batteries nowadays. It’s much more economical to leave the house tied to the grid, and supplement the power with solar. The only time people generally use batteries is when they have no other choice, as in an isolated cabin.

    • Eric Post author


      Thanks for the feedback, but those suggestions probably make more sense in a residential solar installation. Solar hot water might work, but the weight penalty of the collectors on the roof are an issue. RV Solar Electric always involves batteries, since the main times we use it we’re not connected to the electrical grid. So, our setup is like an isolated cabin with propane for heating.