How much space under a flexible solar panel?

[solecollector]

I have two Solara M Power flexible solar panels I’m going to install on the roof of the salon. It is a lagoon 440 - where there is no non-skid... so not a place we normally walk when wet.

My question - those solar panels get hot! I was thinking about building up two stringers to give a 1/2” space under the panels.... thinking the air flow will help with any heat transfer to the cabin through the roof. Has anyone done this? Results?

Thank_steve

[john61ct]

Degradation of the finished surface just below the panels would be a greater concern for most rather than heat gain into the living space.

And make sure to assume the panels will need replacement every few years, and the exact same size may not be available.

[donradcliffe]

I've always put spacers under rigid panels, but I'd worry that the flexible panels might fail faster if they weren't uniformly supported. Maybe some closed cell foam on the back the panel, like a backpacker's sleeping pad.

[Typhoon]

Put it down with this . Sticks great . Never lost one yet and it is high enough to allow an airspace underneath. Also you don’t have to drill holes and it is removable. Put a two inch square every 6 square inches . That will support the panel and allow air flow .

https://www.velcro.com/products/industrial-strength/

Use the extra strength on .

Regards John

[thinwater]

Originally Posted by ColdEh Marine

Put it down with this . Sticks great . Never lost one yet and it is high enough to allow an airspace underneath. Also you don’t have to drill holes and it is removable. Put a two inch square every 6 square inches . That will support the panel and allow air flow .

https://www.velcro.com/products/industrial-strength/

Use the extra strength on .

Regards John

Have you ever tried 3M dual Lock?

[john61ct]

Originally Posted by donradcliffe

I've always put spacers under rigid panels, but I'd worry that the flexible panels might fail faster if they weren't uniformly supported. Maybe some closed cell foam on the back the panel, like a backpacker's sleeping pad.

For the longevity of the panels and PV efficiency, you do not want anything insulating.

In an ideal world use a heat sink material that would take the heat away like aluminum.

I've seen passive solar water heating pads that put the waste heat to good use, help preserve the panels and mount surface, and improve PV output.

[ggray]

Two wall (Double wall, twin wall?) polycarbonate is I believe what is recommended for protecting flexible solar panels from hard spots. Would also provide the air gap you are looking for.

Used for green houses. From my searching, hard to find in the small quantity we would need as shipping would be expensive. I think Home depot carries it in a width narrower than what is likely needed. When the time comes for me to need it, my plan is to fiberglass the joint between 2 panels.

[mikedefieslife]

Originally Posted by thinwater

Have you ever tried 3M dual Lock?

This is what I’m using now. Costs a fortune, but only 6 small squares are needed per panel.

[noelex 77]

Keeping the panels cooler will also help the performance.

[ggray]

I can not find the same twin wall polycarbonate on the HD website that I looked at a year ago. It was clear, about 3/8 inch X18 inches X 6 feet I thought, and reasonably priced.

This is more material, and therefore much more expensive, but you wouldn't have to fiberglass sections together.

I'd want to look at it to see how strong it is.


https://www.homedepot.com/p/Coroplas...6-WT/206084782

[john61ct]

I doubt Coroplast has much UV nor high temps resistance.

Stuff designed for greenhouse use is a good idea, I'm sure lots of quality variability in polycarbonate too.

[Pete7]

Steve, those are high quality and very expensive panels. I have just replaced our solara SM160 after about 12 years use, couldn't afford Solara again. It was held down with velcro blobs which did give it a small 3mm or so gap under the panel. Survived well, we have a picture somewhere with the dog (40kgs) sat on the panel because it was nice and warm.

Pete

[Boston Blackie]

Bruce Schwab has corrugated polycarb sheets for flexible panels

[Anna Sail]

The Solara Power M series are thin, semi flexible solar panels that come embedded with an aluminum backing panel, to diffuse some of the heat. So they've already taken abating heat build up to insure performance.

These are installed on many catamarans, including Lagoons, usually 10 or 12 at a time. I have never heard of an over-heat situation, but, then again, never say never!

Bear in mind, these are not your standard, super thin, flexible panel where a piece of twinwall polycarbonate can be a good addition to get air flow under the panel, like the Solbian panels that Bruce Schwab and Coastal Climate Control sell. Most often these type of panels are sewn or velcro to a bimini which in itself provides the ventilation.

ColdEh's idea of using velcro on a hard surface is good, as long as his reference is for these heavier panels (about 7 lbs) as verses the very flexible panels (about 3 lbs) noted above. He says he hasn't lost one yet, ditto above's "never".

[john61ct]

Originally Posted by Boston Blackie

Bruce Schwab has corrugated polycarb sheets for flexible panels

Good stuff, shape gives better venting and distance than twinwall http://www.greenhousemegastore.com/p...rbonate-sheets