What is the main reason cell crack when building a diy panel

[chuckinnc]

As usual I didn't read about all the problems with building diy panels so I bought some 6x6 fully tabbed cells, they have been setting around still in the box
and I guess it's time to give it a try. My question is what is the main reason they break during assembly? If they are that fragile, then would it be possible to
paint the encapsulating fluid on the face of a cell then place on the glass, seems that would make the cell rigid and crack proof? Anyway I am looking for ideas
on how to lessen the amount of cells I crack. I don't plan on using these panels all the time, just when power goes out or a few times a year when away from the grid. I have been soldering for decades so at least that is one thing I can do well.

[Mike90250]

Just careful handling. They are quite thin, as you have found out.

[PNjunction]

If they are that fragile, then would it be possible to paint the encapsulating fluid on the face of a cell then place on the glass, seems that would make the cell rigid and crack proof?

Not really. While on the subject, consider that the loose cells floating around are those that have not passed the arc-flash test, and therefore they have none of the ARC, or anti-reflective-coating applied to them to save the manufacturer time and money. No way one can do that DIY either. Thus, loose cells with no ARC coating are also much less efficient than the ones the manufacturer saves for his own products.

Still, the only thing a DIY'er can do is purchase quite a few extra, and be careful.

[FunGas]

Yup, I was trying to be careful and cracked 4 building a 36 cell panel even though I used a jig.
Transferring the strings to the glass is probably the most stressful time for the cells.
Plan what you're going to do and get everything ready to hand
The encapsulating resin doesn't cure that quickly, but it gets all over the place if you handle the cells after you pour.

1 tub of Sylgard184 was just enough for my 1m² panel, even after I'd made a "border" around the glass area with silicone sealant (so it didn't get wasted on the edges).

[SunEagle]

Not really. While on the subject, consider that the loose cells floating around are those that have not passed the arc-flash test, and therefore they have none of the ARC, or anti-reflective-coating applied to them to save the manufacturer time and money. No way one can do that DIY either. Thus, loose cells with no ARC coating are also much less efficient than the ones the manufacturer saves for his own products.

Still, the only thing a DIY'er can do is purchase quite a few extra, and be careful.

I knew that those single cells were usually rejects by the manufacturer but didn't know that they did not go through the final production steps and all of the electrical tests prior to being sent to panel install department. Another good point to inform the DIY panel makers.

[inetdog]

... have not passed the arc-flash test, ....

Be careful on the terminology. The cells voltage and current are tested with a flash lamp to speed up the process and avoid heating, and the flash lamp may well use an electrical arc. But among the community of electricians (hopefully including PV installers) the phrase "arc flash" refers to a destructive and dangerous thing that happens when a component of a power distribution system fails and the short circuit produces a very high wattage arc until the overcurrent protection terminates it of the whole assembly is destroyed. A very different thing!

[bcroe]

Yup, I was trying to be careful and cracked 4 building a 36 cell panel even though I used a jig.
Transferring the strings to the glass is probably the most stressful time for the cells.

I would never try to transfer a wired string of cells to glass. That is unless I had a multi
suction cup pickup tool. I wired the cells together on the glass and used a vibrator to get
the encapsulating resin between. Even that didn't avoid all cracks. good luck, Bruce Roe

[inetdog]

I would never try to transfer a wired string of cells to glass. That is unless I had a multi
suction cup pickup tool. I wired the cells together on the glass and used a vibrator to get
the encapsulating resin between. Even that didn't avoid all cracks. good luck, Bruce Roe

What about assembling the cells on the backing material and lowering the glass and encapsulant onto them? Would that work?

[bcroe]

Backing Foundation

What about assembling the cells on the backing material and lowering the glass and encapsulant onto them? Would that work?

I lay the (pretested) cells face down on glass and solder them together, one by one. Soldering
them together seems difficult from the front. Since I don't have a backing, you'll have to
be the one to develop that method. Bruce Roe

[inetdog]

I lay the (pretested) cells face down on glass and solder them together, one by one. Soldering
them together seems difficult from the front. Since I don't have a backing, you'll have to
be the one to develop that method. Bruce Roe

I will pass on that, since I have no intent of building a panel. Just wondering if the technique has been used.