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crcr's avatar
crcr
Explorer
Nov 28, 2019

Routing Solar Wiring from Roof to Pass Through Storage

I'm about ready to install a solar system on our 28' 2011 Jayco TT. Solar panels will be on the roof with the wires from each going to a roof combiner box, then a pair of wires from the roof combiner box going down to the pass through storage, where my solar controller, inverter, etc, will be mounted on a piece of 3/4" plywood opposite the two 6V batteries on the tongue.

To minimize voltage loss, I want to route the wires from the roof combiner box, which will be in the center of the roof at the front of the TT, to the solar controller in the pass thru storage via the shortest possible distance. The shortest route is down through the front center of the TT, between the front cap and the paneling on the inside wall. In the pic below, you can see the inside wall. I removed the decorative headboard which is held by 3 screws, and behind that is the same paneling.

I don't know for sure what is behind that paneling. I recently drilled a hole for another project in the rear wall of the TT, and the insulation there was solid styrofoam. Should I expect that the insulation between the front cap and the inside paneling is also styrofoam? Or would it likely be a different material?

If it is styrofoam, any suggestions on the best way to route a wire from the roof down through it? I can take my oscillating multi-tool and from the inside cut one or more access openings into the front wall, behind where the decorative headboard fastens. For obvious aesthetic reasons, I don't want to cut any access openings into the paneling above the headboard. If the insulation is styrofoam, I wonder how hard it would be to get a wire from the roof through the styrofoam and down to the pass through storage. Does anyone have any experience with a similar project?

Thanks for any tips and suggestions!

15 Replies

  • This idea may or may not help you:
    When I installed my Winegard Traveler satellite dis, the instructions said to route the wiring thru a hole I was to put in the roof... It had some sort of plastic cover to install over it.
    I wasn't too keen on that idea. So I opted to run the wires to the back of the TT (only about 4') and down the roof ladder. All the way to the bottom, then thru the underbelly to where I wanted to come up thru the floor with them. It worked great, and will not ever be a roof leak issue.
  • Unfortunately I'm going to bet your front wall is the same Styrofoam as the rear making it impossible to just push a wire through. What gauge wiring are you running down the wall? Can you hide it on the surface behind some white or tan channeling?
    Link

    It looks like you have cabinets on either side of the trailer that comes down most of the front wall. And I'm assuming there's a night stand table feature under the cabinets leaving a gap between the two of about maybe 18 inches. I would take the voltage drop hit and extend the wire over to the drivers side front corner and come down inside the cabinet. Then it's only a short run of visually exposed channel under the cabinet to the night stand and then across to the batteries. I'll bet after a week you wont even notice the channeling unless you actively remind yourself it's there and look at it.

    You could even put something in front of the exposed channel like a framed picture of the family or a vase of silk flowers velcroed down so it doesn't move during travel.
  • How many watts of panels? What controller? How thick is "substantial"?
  • 2oldman wrote:
    crcr wrote:
    To minimize voltage loss, I want to route the wires from the roof combiner box, which will be in the center of the roof at the front of the TT, to the solar controller in the pass thru storage via the shortest possible distance.
    You can minimize V loss, and ditch the combiner box by wiring in series.


    Thanks, but I have studied this and have already made the decision that I will be wiring in parallel, and I will use substantial gauge wire from the roof combiner box to the solar controller. Parallel wiring because we camp in Forest Service campgrounds and state park campgrounds, and very often during the day, parts of the roof will be shaded, and parts will not. By wiring in parallel, if one or more solar panels has it's output cut drastically by shading, and other solar panels are still in full sun, I will still get a decent amount of amps.
  • crcr wrote:
    To minimize voltage loss, I want to route the wires from the roof combiner box, which will be in the center of the roof at the front of the TT, to the solar controller in the pass thru storage via the shortest possible distance.
    You can minimize V loss, and ditch the combiner box by wiring in series.