Thread: Permanent roof mounted solar panels

Originally Posted by isuzurover

I drilled holes in the leading and trailing ends of the aluminium frame for my panels to allow (some) air to flow through under the panel.

Nice. When mine is on the roof, it's on a mesh roof rack so there's a decent air gap between it and the roof.

I had a chat to a guy that has been installing panels for about 15 years, he recently sold his business but has certainly kept his opinions!

His take was for a small installation MPPT isn't worth it. You can get 30% improvements, but in real life he says you are more likely to see 10% - and a controller that costs 200% more than a PVM. Going through the prices, I could get an extra 100W in panels for the additional cost of a MPPT.. so for now I've just gone with a PVM.

I purchased the panels linked to earlier in the thread.. I couldn't find any others of a decent rating that were less than 400mm wide to fit between the ribs on the roof that were a reasonable price. They arrived today (very fast postage!). First impressions - the quality is pretty poor but hey, $59 each you get what you pay for.

I know this bears no resemblance to reality and has little meaning.. but the controller hasn't arrived yet so I just measured V.

At 5pm in Canberra a panel sitting on the ground in the sun gave me 17.45V. Moving it to that it pointed directly at the sun gave me 17.81V. Moving it under deep shade gave me 16.42V. Placing it on the roof of the 110 as it will be mounted gave me 17.94-18.58V as some clouds were passing over (left it there for 30min to 'warm' the panel, then took the avg of 5min with the multimeter connected.) Full cloud gave me 16.85V.

The panel is supposed to give 20V (conditions for this are not mentioned, it is just what is says on the panel.).

When the controller arrives, and I can connect a load to it I will post amps.

I will mount them like this once I pick up some ali angle.

Do you have a nice way of getting the electrikery down inside the vehicle, or is it a simple hole-in-the-roof and sealant job?

EDIT: If they're going to be permanent I'd be seriously thinking about just running a bead of silicon down the sides between the panel and the roof rail.
Easy enough to cut off later if you want to remove them, and no holes to drill etc.

Steve

Short answer is no.. I don't feel too bad as the roof already has holes in it for the mounting of the AC unit in the back. (that doesn't leak).

I will probably use rivnuts and sealant for the panels, and some sealed cable passthroughs that I'll pack with sealant for the cable.

IF you're going to mount them like that I strongly recomend drilling a dozen or so 5mm holes at the leading and trailing edge of each panel or lifting them up a couple of mm.

it wont be enough to make the panels run "cool" but it should be enough to stop them burning at the solder joints to the leads.

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Mounting solar panels with steel screws and roof and gutter silicon is lucky to last a year, sikaflex these on, they are fantastic

Although Marsol are **** to deal with, the have forgotten a few of my orders

I always make my own alloy angle brackets and use alloy rivets - never had any problems. You can position the alloy brackets to raise the panel off the roof. Pic is of recent install on shed roof but I did this on my 300Tdi and 300,000km later no probs (80w mono panel on Deefer roof), and that was a lot of off-road through 12 years of survey work. Did same with 64w panel on roof of Puma - 60,000km no probs. Use a cable gland and drill the roof - they don't leak. Pic shows cable gland for rear work light - same deal flat on roof for panel but no pic. Did a quick pic edit to show gland on Puma :-) You end up drilling lots of holes in the roof for rivets, gland, etc but none of them ever leaked and what the heck - it's my roof

Originally Posted by Blknight.aus

IF you're going to mount them like that I strongly recomend drilling a dozen or so 5mm holes at the leading and trailing edge of each panel or lifting them up a couple of mm.

it wont be enough to make the panels run "cool" but it should be enough to stop them burning at the solder joints to the leads.

Definitely the plan to do both.