How to tell the difference between Grade A and Grade B cells.

[apctjb]

It could have failed for something other than capacity, it could have high self discharge or higher internal resistance than spec.

Agree; that why it would be marked B, but with its capacity....

 

[RandyP]

It is my experience, after reading many posts about EVE Prysmatic LifePO4 cells, that there is no such thing as an Grade A, B, C or D cell. EVE tests their LiFePO4 cells against the specs they were built to, as they are being produced and after production. The Chinese governmant has a standard for all automotive Lithium Ion cells that requires the manufacurer to test the cells they manufacture to be per the specs they were built to. Those cells that pass these tests are considered 'Automotive Grade' cells (not grade A cells). If the cells do not meet the manufacturers specs, they are not 'Automotive Grade' cells. They can not be sold to the auto industry for electricc vehicles (i believe the chinese govt does this to eliminate catastrofic battery failure with smoke and fire in automobiles. How many of this type of failure would be tollerated by the customers buying EV's ?). The manufacturer auctions the failed cells off in large lots of cells to the highest bidder, recapturing some of the mfg battery cost. These "non-automotive grade" cells are resold thru many businesses as Grade A, B or C. Sometimes as solar grade or communications grade cells. They are sometimes sold at 1/2 the price of 'automotive grade' cells. The RESELLER dubs them grade A, B or C as they see fit.
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Grade A, B & C lifepo4 cells are a resellers designation game, convincing buyers to get more cells for less money than if they bought 'automotive grade' cells. In some cases the buyer is happy to have the cheap batteries, as they meet his needs (Low power solar systems) and the buyer is not critical of their short comings (Provide less than advertised AH or WattHour rating, shorter life, different dimensions, swelling, ect).
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The question should be "Am I getting 'Automotive Gade' LiFePO4 cells when I buy auctioned reseller 'Grade A' LiFePO4 cells.

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Just my understanding of this mess.

 

[apctjb]

EVE has Grade A and Grade B. Marking tested capacity would at least let buyers know what they are getting when buying grade B.

 

[RandyP]

View attachment 113221

EVE has Grade A and Grade B. Marking tested capacity would at least let buyers know what they are getting when buying grade B.

-EVE does not have any cells with an 'A' on that code designator. Just the 'B', meaning that they are not 'automotive grade' cells. I applaud them for doing this, I think they are trying to clarify that some auctioned off 'non-automotive grade' cells are being resold as 'Grade A' by aftermarket sellers in the gray market.
-Marking test capacity (AH or Watthours) would not make them Automotive Grade batteries. Their internal resistance, dimensions or internal cell component configuration (tested by something akin to x-ray or CAT scan technology) might be why they are marked Grade B, even if they do meet their capacity rating. Any shortcoming in meeting the specs makes them reject cells, and their life expectancy can be shortened by being out of spec.

 

[Goboatingnow]

You seem to be the exception, or you are exceptionally naieve (you dont test the batteries you recieve before putting them in serice).

I have bought some batteries but yes I have tested them and in one case had a dispute happily resolved.

 

[Alkaline]

You seem to be the exception, or you are exceptionally naieve (you dont test the batteries you recieve before putting them in serice).

Or full of it.... Nothing but good experiences form Aliexpress? I guess you must have "worked it out with your seller" 530 times then

 

[Gazoo]

I have had a few good experiences with Aliexpress and zero bad experiences. But none of the items I ordered were batteries and I would never order batteries from them. So many on this forum have posted bad experiences ranging from bloated cells to capacity less than advertised to fake QR codes. Alibaba is better but one must be cautious when ordering from them as well.

 

[Gazoo]

I have bought some batteries but yes I have tested them and in one case had a dispute happily resolved.

I am a little late here but just curious. Out of the 530 orders how many were for batteries....if you don't mind my asking.

 

[Goboatingnow]

I am a little late here but just curious. Out of the 530 orders how many were for batteries....if you don't mind my asking.

16 approx orders for batteries of various Lithium technologies and types.