How do I check LifePo4 cells quality against the price before buying?

[flashmark]

Hi,

I'm planning to buy LIfePO4 cells from the local market.
There are 3 choices at the moment.

1. 125Ah - Eve grade A/ Brand new (100 USD - 1 cell)
2. 200Ah - CALB grade A / Brand new (110 USD - 1 cell)
3. 200Ah - Grade B ( 90 USD - 1 cell)
Even though sellers are telling about the qualities I'm not sure the information is correct.

Before buying,

1. How do I check whether cells are Grade A - brand new cells?
2. Since there is no QR code, how can I know the manufacturing date?
3. How do I check the actual capacity and internal resistance of cells?

your help is greatly appreciated.

 

[Don B. Cilly]

You should ask a reputable vendor.
Personally I (and it seems quite a few people on this forum too) have had good experiences with Amy Wan of Shenzhen Luyuan.
If you use the "Chat Now" Button there, it's the best way to contact her - keeping in mind Cantonese time zones.
-

 

[Aloys]

Generally, the Grade A cells shall have QR codes. If you see no QR code on the cell, 95% are not Grade A/brand new cells.
Also, if there are screw bolts on the positive and negative of the single cell, 99% are not Grade A cells.
As for the actual capacity, you need to test them and find out the result...

 

[Alkaline]

No way I would pay 90/cell when the grade A (assuming it really is a grade A) is only 110.

BTW the way to know for us is to ask for a manufacturers individual cell report.