Bendable panel Heat question answer by Renology Tech Dept

[RC Pilot Jim]

Recently I emailed Renology with the following question:


Many folks say the back of a standard panel gets hot and should have a separation between roof and the panel to allow for cooling.





I never considered this issue when I glued our Renology bendable panel, so......Is heat an issue? And if so am I loosing amps with it GLUED down?

Following is Renology answer:

"........ you will be losing some voltage/power due to the increased temperatures that occur from a lack of cooling on the back face. Typically, the temperature of the bendable panel cell will be the same as the surface the panel is attached to, ie the roof. The temperature coefficient of this panel (for power) is -0.38%/°C of maximum. This means that if the panel were to get to say 57°C (160°F) during a summer load, you’d be looking at a power loss of about 12W. This may sound bad, but with the normal operating cell temperature of 47°C, you already lose about 8 W from the rating. So due to the mounting you’re looking at 12% loss versus the normal 8% loss which is negligible considering all the other variables at play with the panel."

Hope this helps!


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[SIZE=11pt]Chris McNamara, B.S.M.E., E.I.T.[/SIZE]
[SIZE=11pt]Technical Engineering Manager[/SIZE]





[SIZE=11pt]Engineering & Technical Support Department[/SIZE]
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[SIZE=11pt] [/SIZE]
[SIZE=11pt]14288 Central Ave.[/SIZE]
[SIZE=11pt]Chino, CA 91710, USA[/SIZE]
[SIZE=11pt](909) 287-7100 Ext. 301[/SIZE]

 

[DonC]

This is a more technical discussion than the response I got from Renogy, but the same bottom line - it doesn't make much difference how you mount it. Just make sure it is securely mounted whichever way you do it.

I've not communicated with other solar panel manufacturers, but Renogy is really responsive and helpful.

 

[alano]

"I knew that!", he said looking around shiftily after gluing his panels directly to the roof of his camper.

Alan

 

[RC Pilot Jim]

ALAN I think Chris says you and I ....and a lot of others are ok with the panel glued down.

 

[kmacafee]

IMHO, an 8-12% loss of output is not insignificant. Add shade to any part of the panel and the deficit gets even bigger.

I have the yakima tracks and I will build something utilizing those.

 

[DrJ]

Jim,
Thanks for taking the time to research that and forward the information to us. I think their answer is right on. My panels work great and the power loss by applying them directly to the roof is quite minimal. I think it's the best set up possible.

 

[RC Pilot Jim]

Right " K " ...however it's only 4% additional.

Actually the panel has yet to produce 5.7 amps because the percent of discharge has not been lower then 82% to date.

Note: I tested the panel when purchased and verified the static output was 5.7 amps when tilted toward the sun on a cloudless day. Based on the instructions the battery has to be discharged 50% (around 12.1 volts) and the sun has to be almost directly overhead to generate stated amps when installed on the roof.

 

[Coblue]

RC- Thanks so much for posting Renology's answer. I've been wondering that for some time.
Seems like a white aluminum roof would be a decent heat sink.
K, please post up whatever you do- maybe even a "on the roof" vs "above the roof" comparison.

 

[kmacafee]

Will do. Jim -- thanks for posting the response from Renology.