bubbles under eva film

[Jaiman]

Hi all am new to solar and am doing some homework before venturing into DIY solar, in my quest for the best way to encapsulate cells I note that unless eva is applied under vaccum it tends to trap small bubbles which have a detrimental effect on charging capacity and was wondering if anyone has tried a pin prick into the bubbles to let air escape or would this allow moisture and air back in or is there a better quicker way to do the trick.
PS while I'm here what is the best type of cell to use mono or poly and what are the views on Chinese components?
JAIMAN

[Mike90250]

The EVA is soft when hot, and the vacuum pulls it tight against the cell. If you get a bubble, it won't go away with just a pin hole, you need to heat and vacuum it, and then somehow, seal the pinhole.

[inetdog]

Hi all am new to solar and am doing some homework before venturing into DIY solar, in my quest for the best way to encapsulate cells I note that unless eva is applied under vaccum it tends to trap small bubbles which have a detrimental effect on charging capacity and was wondering if anyone has tried a pin prick into the bubbles to let air escape or would this allow moisture and air back in or is there a better quicker way to do the trick.
PS while I'm here what is the best type of cell to use mono or poly and what are the views on Chinese components?
JAIMAN

The problem of bubbles that you describe is why commercial panel manufacturers not only apply a vacuum to the underside of the EVA but also apply several times atmospheric pressure above the EVA. This helps to assure that the film seals tightly to the cells and the substrate without any bubbles.
Without at least vacuum application, you will have a very hard time avoiding bubbles.

As for mono versus poly, you can get good cells in both types, with comparable performance. Your choice should be made more on the basis of whether you are getting good quality cells than on the exact type. (IMHO)

Chinese components can be quite good. And they can be very poor. A reputable "name brand" manufacturer, along with UL listing rather than some other vague "built to xxx standards", are two indications to look for.

[elhifnawyplast]

polycrystalline Vs mono-crystalline

[QUOTEPS while I'm here what is the best type of cell to use mono or poly][/QUOTE]
polycrystalline cells performance is better in cold surroundings and mono-crystalline cells performance is better in hot surroundings

[russ]

[QUOTEPS while I'm here what is the best type of cell to use mono or poly]

polycrystalline cells performance is better in cold surroundings and mono-crystalline cells performance is better in hot surroundings [/QUOTE]

And you can see the difference? Not really.

[greggers]

The problem of bubbles that you describe is why commercial panel manufacturers not only apply a vacuum to the underside of the EVA but also apply several times atmospheric pressure above the EVA. This helps to assure that the film seals tightly to the cells and the substrate without any bubbles.
Without at least vacuum application, you will have a very hard time avoiding bubbles.

As for mono versus poly, you can get good cells in both types, with comparable performance. Your choice should be made more on the basis of whether you are getting good quality cells than on the exact type. (IMHO)

Chinese components can be quite good. And they can be very poor. A reputable "name brand" manufacturer, along with UL listing rather than some other vague "built to xxx standards", are two indications to look for.

so what about Dow Corning® PV-6010 Cell Encapsulantat? looks ideal on paper

[Naptown]

polycrystalline cells performance is better in cold surroundings and mono-crystalline cells performance is better in hot surroundings

And you can see the difference? Not really.[/QUOTE]

Actually you can see the difference. Poly's tend to be a cobalt blue color and moteld surface where Mono's tend to be a uniform black color.

[russ]

And you can see the difference? Not really.

Actually you can see the difference. Poly's tend to be a cobalt blue color and moteld surface where Mono's tend to be a uniform black color.[/QUOTE]

Difference in production over time?

[Naptown]

Actually you can see the difference. Poly's tend to be a cobalt blue color and moteld surface where Mono's tend to be a uniform black color.

Difference in production over time?[/QUOTE]

Really depends on the doping. But poly's will have a burn in period of about 30 days where they will lose about 3% then the process slows down

[joeprinter]

Eva Bubbles

I have used EVA exclusively on my solar builds, never have applied vacuum if you take your time, an apply heat to both sides you will not have the bubbles. Eva is very forgiving. Remember to keep your distance however if the heat, may take a bit longer but better than blowing a hole in it. I just got a box of EVA in yesterday 5 lbs for $22 an 15 shipping. I cant offer any advice on the liquid in that I have never used it. I put a piece of eva down Cells then a piece on top, like a solar sandwich..