Buying A grade solar cells

[inetdog]

Ban this Chi-Com idiot. Geez digging up a 4 year old thread.

Since the linked site appears to be non-commercial, I think I will just warn everyone that any information there should be taken with a grain of salt, as they would for any internet site that they do not know the history and reliability of. Even information on this forum will vary in quality depending on the poster.

I agree that piggybacking onto a dead thread is not polite behavior.
But please refrain from personal name calling attacks on members. Attack the post, not the poster.

[Sunking]

Grade A solar cells can be bought from the manufacturers, however MOQ's apply. They won't easily sell a couple of hundred pieces, unless it's a sample order..

As Grade B solar cells are supposed to have similar power output as Grade A, but visually deviate, the only way to distinguish is to identify their visual defects.

Need photo examples of different grade solar cells? Find here a complete overview of Solar Cell Grading (A, B, C, D Grade solar cells) with Photo examples:

Cheers,

Peter

Ban this Chi-Com idiot. Geez digging up a 4 year old thread.

[PNjunction]

Don't overlook ARC Coating with crap cells!

Also don't forget that when a manufacturer does the flash test, and find that the cells do not meet the GRADE A status, NO ARC Anti-Reflective-Coating IS APPLIED!

Lack of an ARC coating because the cells are not grade-a is a major problem from losing effectiveness at off-angles of sunlight.

I can also go into business calling my loose cells any grade I want, and to my knowledge, there is no regulation or oversight to be accurate! Talk about caveat emptor.

[FunGas]

look up user mlsun

Got mine from that seller and was very pleased.
The cells measured exactly what was quoted or better.

it's not that economical

This is also true, similarly rated ready-made panels work out cheaper.

[PeterGr]

Grade A solar cells can be bought from the manufacturers, however MOQ's apply. They won't easily sell a couple of hundred pieces, unless it's a sample order..

As Grade B solar cells are supposed to have similar power output as Grade A, but visually deviate, the only way to distinguish is to identify their visual defects.

Need photo examples of different grade solar cells? Find here a complete overview of Solar Cell Grading (A, B, C, D Grade solar cells) with Photo examples:

Cheers,

Peter

[dataman19]

Grade A cells put out over 95% of theoretical rated voltage under "Solar Test Lamp" light testing (not actual sunlight). They also Produce over 90% of theoretical Rated Open Circuit and Loaded Circuit current under the same "Rated Test Lamp" Testing.
...
How do they determine theoretical rating? By the surface area, cell Wafer composition and manufacturing quality. A given square of any given photovaic cell material has a given electrical property. The only variable is the ability to laser etch the conductive channels (a production process, and one that every cell production plant holds under lock and key).
..
Yes Grade A cells do not exhibit a lot of Micro Cracking/Fractures. This is tested under a microscope. But micro cracking in itself is a natural flaw in ingot production. The presence of micro cracks is not a reason for downgrading a cells quality to "B" instead of "A". But a certain amount of overall micro cracking in the wafer (determined by the manufacturing or receiving plant's Quality Control Standards - which vary some what from one company to the next) could result in a batch of cells being down graded to "B".
...
No! They do not test each and every cell, they do random sampling. Yes, it is conceivable that you could get some "A" Type cells in a few batches of "B" Grade cells - but not too likely. Look at it this way. A Silicon Ingot is sliced (like you would slice balogna or Ham) on a slicer. So if there is a twig embedded in the balogna - then all the slices that were done the length of the twig would have the same flaw (a twig...). So the slices before the imperfection could be "A" Grade and the slices after the imperfection could also be "A" Grade. But the slices containing the imperfection would all be "B" or even "C" Grade. Given the fact that they get hundreds of slices off any one ingot - it stands to reason that they only do in depth testing analysis on so many out of so many total slices. This results is a predictable analysis of the over all batch of wafer slices.
...
Yes - Grade A cells are scarfed up by the Solar Cell Fabricators. Yes - Surplus cells are generally "B" Grade Cells, some have even resorted to selling "C" Grade cells on eBay. "B" Grade cells once encapsulated have a high degree of reliability as compared to "A" Grade cells. Their weakness is in stresses encountered prior to encapsulation. "C" Grade cells are extremely fragile and tend to break under the stress of soldering and laminating. "C" Grade cells will also most likely fail under daily thermal shock encountered in their intended operational environment. So panels built with "C" Grade cells would probably not last 10-25 years, but would most likely fail withing the first 1-3 years.
...
The largest quality variation in PV cells is between the "B" Grade and "C"Grade cells.
But if you are experimenting and practicing - "C" Grade cells "are a whole lot less of an expense. Why waste good cells in practice.
...
Dave
dataman19

[Bob_man069]

Everbright is where I ordered my cells from. (off ebay). I ordered 80, received 88 and only had 1 cracked cell. All others put out the correct power as indicated.

Hope that helps.

[russ]

As this is something many ask about it can stay.

Does anyone have comments to make on Everbright Solar?

Good or bad will help others.

Russ

I have bought all my mono's from this guy. He has them cheaper on ebay. All the one I have recieved so far, (about 160), have put out excatly what he claims. he sends extra in case some get broken in shipment.
Sorry if we arent supposed to post product websites

http://www.everbrightsolar.net/mono-crystalline-solar-cells.html

[rollandelliott]

any diy web sites showing panels failing from bad cells?

do you folks have any websites or other data that shows panels failing from bad cells? all the diy web sites i've read talk about panels failing from bad encapsulation/water vapor, etc. Never read a story about panels failing from bad cells.

and yes I meant currnet not voltage in my previous post
just measure the current and that way you can tell if a cell is bad pretty easily.

[russ]

Makes me think of buying silk carpets in India - there are many terms that tell you what you are really getting that I don't remember now but I suppose some of them would roughly translate as, 'fools silk'.

As long as no one that knows anything about a silk carpet ever looks at them all is well.

Russ

[Mike90250]

most b grade cells on ebay have sharp edges, very small chips and other visual defects, hence the discount.

Actually, those would be grade C, with visible flaws. B's have flaws on the microscopic level.

[Sunking]

can't one just hook up a voltmeter to one cell in sunlight and test them themselves?

Sure you can do that. All solar cells will have the same voltage regardless of the grade. It is the current that will get you.

[Mike90250]

Grade A cells have no microscopic flaws or cracks that propagate over the coming years, no funky metalization, and several other features (even AR & SA coatings, batch testing ( if too many parts in a batch fail, the whole batch is rejected))..

[rollandelliott]

can't one just hook up a voltmeter to one cell in sunlight and test them themselves? most b grade cells on ebay have sharp edges, very small chips and other visual defects, hence the discount.