All true, but I think you're missing what I was saying. I think one of the liabilities of surface-mounting an adhesive-backed
solar panel directly to a
fiberglass trailer's shell is not that the
solar panel's efficiency suffers as it heats up, but that the trailer's occupants suffer as the panel absorbs the Sun's heat energy and transmits it into the trailer. An amorphous
solar panel may work really well at 185°F, but I get distinctly grumpy at temperatures over 100°F.
Ditto panel size. After their first few hours exposure to sunlight (Google up Staebler-Wronski effect and look
here to see why this may become less of a factor in the future), amorphous panels have been 7-8% efficient at converting
solar energy into
electrical in direct sun; crystalline panels are 16-21% efficient, so you need less than half the panel size to obtain the same generating capacity.
It all adds up, in my mind, to thinking that amorphous panel installations may wind up being the better application for large, fixed roofing structures that don't interface directly into living spaces, but not the best choice for the tiny roof of our trailers that are right on top of us, or for portable
solar panel arrays that we move to a sunny spot when we set our trailers up.
YMMV
Quote:
Originally Posted by jlgothard
>As for sticking an amorphous panel directly to your egg's roof, I'm not >sure that's a good idea.
This data pertains to Flex Energy's PVL solar mats (manufactured by Uni-Sol). The normal operating cell temperature of this thin-film product is 50°C to 70°C (with no back ventilation) and the maximum Recommended Roof Temperature is 85°C (185°F). Putting them on an RV roof should not pose any problem at all. I have two such mats on my Class C.
>The polycrystalline panel set less than half the size, it puts out more >power than the amorphous panels because amorphous panel output >rapidly degrades once you put them out in the sun*.
I'm certainly no expert, but research indicates that the reverse is true. Polycrystalline products become less efficient (as much as 20% less efficient than a PVL mat at normal operating temperature) as the temperature rises whereas PVL products do not. Indeed, in daily use the PVL mats will generate power for longer than a crystaline panel because they have an exceptional tolerance for low light levels and shade - so they will keep generating long after crystalline panels have stopped. According to Mount Union College in Ohio the mats remain 80% efficient even under two inches of snow. So there are cases where you might have a higher rated crystalline panel that actually generates less power than a lower rated PVL mat on a daily basis given a broad range of weather conditions - like those that we experience in the real world
There's simply too many benefits from a PVL product to ignore, especially if you're RVing or Overlanding.
Julian
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