Sciencemadness Discussion Board

Resin Coating for shattered Solar Panel?

BobD1001 - 7-8-2021 at 08:06

I recently bought four perfect condition 330w solar panels for a great price, alongside the good ones I bought, the seller had one that the glass was shattered on and only wanted ten bucks for it. Still produces plenty of energy, but just bad glass. I would like to coat it in some way to help weather resistance and appearance, but also know that many coatings will block certain wavelengths of light, which would obviously impede the efficiency of the panel. From what I have read, solar panels convert mostly visible light, and some infrared, into energy.

Does anyone know of a good resin coating I can use on this solar panel, which will hold up (preferably not yellow horribly) and still allow broad spectrum wavelengths pass through it? I am thinking I can use a UV resistant epoxy resin or two part automotive clear coat, since only about 4% of light hitting the surface of earth is UV, I wont loose that much efficiency (assuming the panels even convert all the UV into electrical energy which my reading indicates they dont).

Any insights are greatly appreciated... Hoping someone here has tried this before.

Sulaiman - 8-8-2021 at 00:09

Clear low viscosity silicone 2-part resin and a new sheet of glass should be ok
(I bought my resin from Poland ... forgot the brand, Plastapol or something similar?)
(I purchased low iron content glass - not standard window glass, which has a greenish tinge)
Ordinary cheap agricultural glass or window glass is ok, thinner=better.

PS do not use hardware store silicone sealant that releases acetic acid for a long time - surprisingly corrosive to copper.

Small solar panels (1W,3W) have just a layer of epoxy resin over the cells on a fibreglass/epoxy pcb.
I used some and after about a year I polished the surface to remove oxidation/erosion,
but the output did not seem much different than new
(almost new, I'd used them for other projects earlier, also I had no reference illumination)
But this was in UK - only a few weeks of the year can give a suntan.
Also, winter output A.h/day was about 1/10th of summer.

I never finished my 2x 1m square 100W panels as my back failed and soldering cells together was too much leaning over for me.
I never even got to use the silicone resin.
I did do quite a lot of research but if others disagree based on experience then that would be better.

[Edited on 8-8-2021 by Sulaiman]

B(a)P - 8-8-2021 at 03:34

I think Big Clive did something on this on his you tube channel some time ago. Might be worth a search.

andy1988 - 8-8-2021 at 21:24

I bought a bunch of cells but never got around to making panels.
Solarpaneltalk.com and fieldlines.com have good info/guides.

Anything more permeable than tedlar likely won't allow the cells to last more than a couple years due to moisture corrosion according to many forum posts.

IIRC I read a thread with nice pictures where the author encased the cells in silicone, without a glass front (or maybe it was glass front & sicilone back?), but that didn't last more than a couple of years due to moisture corrosion.

Here was the most relevant advice I could find at a glance along those lines:
Quote:
All the different parts in the panel (Glass, EVA, Tedlar) are designed to protect the cells. There are no other suitable parts to replace those.
Use shower door glass, you loose a couple % in light loss. Skip the Tedlar, and your cells soak up moisture and rot out in a couple years. Same for bedding them in silicone. Epoxy might be clear for a year or three, and then it yellows [1].


EDIT: But I suppose the context of your broken panel may be different, if you're just filling in the cracks or the cracks are the only area through which water will permeate, rather than the entire front/back.

If you want it to last longer than a couple years outdoors one option would be to make a separate enclosure and get clever with silica gel beads (or other desiccant) to absorb moisture as this author suggests [2]. In addition to having sealed the primary panel as best you can with EVA/silicone or whatever. Maybe one of those uv-cured glass to glass sealants might be an option.

Other than that, apparently clear tedlar exists. Marketed as a backsheet for bifacial cells (bifacial cells produce power from both sides). But a roll of this likely exceeds what you saved on that discount panel.

Here is a reference on oxygen and water permeability of various films [3]. EVA is in that table... hot glue sticks are EVA. I'm sure you can find other more relevant references for products you consider.

[Edited on 9-8-2021 by andy1988]