Solar panel wire / roof penetration

[noseoil]

I can't find the thread in the search. Could someone please point me at the roof penetrations they used for solar wiring on their builds? I want something which is rain-tite & permanent for the wire running through an aluminum skin & 1/8" top panel.

[MtnDon]

I don't have a link, but a liquid tight fitting will help solve the problem of a safe penetration. HD link They have a rubber grommet that is compressed around the wire. I would not go through the roof myself. I would go through the wall. Less chance of a leak in most cases and IMO. That is my plan for when I get around to selecting some PV panel(s).

[lrrowe]

I have given this need a little thought and like MtnDon, I would prefer not to run wires through a hole in the roof. One idea I have is to run the wires towards the rear of the trailer and mount a waterproof plug/receptacle similar to this design:

https://www.perfprotech.com/waterproof- ... duct/31495

[MtnDon]

I have another thought on this... I have a weatherproof charge controller coming from Midnite Solar. FYI it uses a couple of the water tight fittings on the lower edge of its case. I plan to mount it on the exterior of the left rear cargo door, under the A/C unit. I am thinking of possibly running the wire from the PV down the left rear corner near the hinge line. I might encase it in conduit or tubing of some kind from the roof down to the charge controller. That would be secured to the trailer with cable / conduit clips. From there the wire to the batteries would run down that left rear corner and under the floor. There it would penetrate the floor and run across the inside to end up at the batteries on the right rear inside.

In our case the left rear cargo door does not get opened and closed much.

[lrrowe]

MtnDon, if you are alking about this one:
http://www.midnitesolar.com/pdfs/spec_s ... ntBack.pdf
I think I can visualize the concept. But why go thru that level of complication and also leave that $125 controller outside and accessable to thieves? Why not just take that cable from the panels over the top of the back panel over the doors and run the cables through that same panel at the top. If not my connector idea, use a waterproof connector similar to the ones used on the controller bottom? And then connect it to the controller.

[MtnDon]

Partly because maybe I don't want it inside. The LED's are bright enough to be possibly bothersome as the unit would be located right where our heads are in bed. Don't want long wires to allow putting it up front. It's still just one of a few options, another being to place the CC inside and in the shower area where the shower wall would block the LED light. And it is weatherproof That would need a little more wire but not really too big a deal. Not sure where I would run the wires inside though.

[lrrowe]

Understood. And if followed my suggestion, then the wire from the farthest panel could be long too, say 22 feet versus maybe 10 ft for the most direct route down from the top. I guess I would have to consider the voltage cost of such a long run, if it is an issue at all. And if I kept the controller inside, could I find a lower cost, non-waterproof, model?

[MtnDon]

Using 15 volts, 15 amps and 10 AWG wire a 10 ft run has 2.4% voltage drop; quite good. 25 feet produces 6% drop which I find objectionable. Larger wire could be used once the 10 AWG MC4 wire enters the inside. That would help.


There are lower cost non weather resistant CC's, but mine was very low priced as a beta tester..

[lrrowe]

That loss is too much, I agree. Let me ask this question about voltage loss. If the distance from the panel is 10th to the controller and results in a 2.4% loss in this example, and then you run the wires from the controller to the batteries for 10ft, is the loss another 2.4% of the already reduced voltage? Or does the calculation result still end up at 6.4%?

Does this question make sense?

And sorry Noseoil, if this is hijacking your post. If it is, I will take this to a new post.

[MtnDon]

... is the loss another 2.4% of the already reduced voltage? Or does the calculation result still end up at 6.4%?

The loss is cumulative.

[Shadow Catcher]

I found and used a Perko Watertight deck connector which accepts 10 ga wire and it has not leaked and works. We do have a high voltage panel so voltage drop is not a concern. Typically I see better than 35V at the controller.

http://www.downwindmarine.com/Perko-Watertight-Deck-Connector-Polarized-2-Pin-p-91001842.html

[noseoil]

No worries about the thread, it's all good and I enjoy reading about things related to questions I ask. I learn good stuff that way. Any way, here's what I found after a long, long search online.

I think a pair of these mounted side by side should work out very well for my needs. The problem is getting the power in through the roof and keeping everything else out (bugs, dust, water, etc.). They're made in different sizes for anything from small wire stuff to the larger cable types, so I just need to measure the cables I have and go from there. The hole will go through the top panel (aluminum skin & 1/8" baltic birch), then back along the headliner & into the cabinet back, which is the electrical chase panel behind the TV mount. I can face them aft and locate them under the solar panel, where they will be out of the way, in the shade, & bedded securely for no leaks. I think this will work well enough for a solar panel. Might be a bit of overkill, but it should work well enough & last forever. They just use regular EMT type nuts (1/2" NPT), so no problems with the installation.

[dales133]

The other thing you could use is called a cable gland. I think it would be a better option for what you want mate.
They are avaliable in plastic or stainless steel and designed for this very purpose.

https://www.google.com.au/search?q=cabl ... CAYQ_AUoAQ

[lrrowe]

I think I will climb up on the ladder and look at my Fantastic Fan to see if there is space to add one of these connections (cable glands) to the side of the fan sleeve assembly that is above the roof line. If so, it would satisfy many needs such as no more holes in the roof and able to shorten the wire run in feet.

[MtnDon]

Bob, I can also paint the housing to match the trailer so it won't be as apparent.