JA Polys - mottling

[SolarRoofSols]

Does this level of mottling look about right to you guys for a 250w JA solar poly module?

We have been asked the photo has been sent by a company who we quoted for but they went with another installer offering a cheaper price - the installer has now gone bust. We've only installed JA monos before.

Could just be the way the light is hitting the panels but it looks quite extreme compared with other polys we have installed.

 

[jason121]

Looks like the old Suntech module, Renesola have the flakes to, something to do with the manufacturing process.

 

[Meggerman]

Does this level of mottling look about right to you guys for a 250w JA solar poly module?

We have been asked the photo has been sent by a company who we quoted for but they went with another installer offering a cheaper price - the installer has now gone bust. We've only installed JA monos before.

Could just be the way the light is hitting the panels but it looks quite extreme compared with other polys we have installed.View attachment 23405

Lots were like that although must say they do look more pronounced. ET solar were another one that looked similar, but cheap panels so sold well. Tell customer they should have gone with you and "you pays your money and takes your chance"

 

[Marvo]

It's strange how there's several patterns that repeat themselves several times. They're not random.

 

[Meggerman]

It's strange how there's several patterns that repeat themselves several times. They're not random.

Yeah, that's what they are all like, it is definitely a manufacturing thing and not a defect.

 

[solarsavings]

It's strange how there's several patterns that repeat themselves several times. They're not random.

The pattern(of the cells) repeats because they are wafer slices of a multicrystalline block.

 

[Marvo]

Ahh, that explains it. Didn't realise the wafers were sliced, I kinda assumed they were 'grown' individually.

 

[happysteve]

Hi Marvo,

Solar cells can be made using a different process: the string ribbon process are "grown" individually, so would have individual/unique patterns of grains. This one must've been chopped up and sliced.

(Don't know much about solar panels, but I know a fair bit about measuring microstructure and crystallographic orientation using laser ultrasonics... never applied this to solar panels, might be interesting to do so...)

 

[Gavin A]

answer - that's what cheaper panels look like.

I don't personally see that there's any way those cells can be anything like uniform in their power characteristics across the cell, but I've yet to be able to blag one of those million quid machines to test the panels to be able to verify this... it's on my christmas list mind, so maybe if I've been really good all year I might find one in a stocking next winterval.