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urbanMark's avatar
urbanMark
Explorer
Jan 30, 2017

cable routing for solar - vent pipe or drill roof?

Hello Everyone,

First post here. I'm sure this has been asked before and I did search but came up empty.....

I'm installing solar on my 2011 Eclipse Milan 25RKS TT. I've already built a custom enclosure for my dual AGM batteries and wired up the MPPT controller, breakers, fuses, disconnects, etc (I'll add some photos if I can figure out how), but the one remaining task is to route the cables from the roof to the controller. My fridge is near the rear of the trailer, so that isn't an option, and unless I want to tack conduit to the outside of my trailer (yuck), I'm looking at one of the following:

1. Use the grey water vent pipe. This comes out under the bathroom sink and is conveniently next to where all the electrical comes up from under the trailer - so I wouldn't need to cut a new hole in the bottom of the trailer. It would also keep the wiring out of site and away from storage areas. My concern is fishing the wire out of the pipe and sealing the hole well enough to prevent a smelly trailer.

2. Drill the roof over the bedroom closet. Straight forward and shortest cable run, but the closet is over the main storage bay - so wires would run through the storage bay (to get under the trailer) and would be a snag point for loading/unloading the storage area. The closet is also quite narrow and I'm sure the wires would be visible no matter how well I tried to conceal them.

Anyone had experience with the vent pipe method? Other options I should consider? Ideas for dealing with the wires through the storage bay?

Thanks!
Mark

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  • Almot's avatar
    Almot
    Explorer III
    Jan 30, 2017
    urbanMark wrote:
    ...the one remaining task is to route the cables from the roof to the controller. My fridge is near the rear of the trailer, so that isn't an option

    Not an option because ....? Too long run or don't know how to route it inside in aesthetically pleasing way?

    Voltage drop with 24V panels in series isn't a big issue, with #10 MC4 cable (you cut it in half) at 30-40ft run V-drop will be negligible. With more than 500W or in parallel - can't say, need to run the numbers. There are also #8 MC4 extensions for those who need it.

    I did it this way with 2*250W in series, #10 MC4. About 18 ft from fridge vent to trailer front, inside routing through the wall cabinets, and then under the Wiremold cable covers when not in the cabinets. 7ft drop down to batteries plus another 5 ft interconnect btw two panels, total 30ft one way. According to Southwire calculator this results in less than 2% voltage drop.

    There isn't much need to drill the roof with 24V panels. With 12V panels and PWM - yes, those are often installed with a hole in the roof and junction box.

    Yes, somebody run it through the black tank vent - not the grey tank, as I recall - doesn't matter, it's not venting to inside anyway. Pics are posted on that List.

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