I took a risk and ordered 32x 320 Ah LiFePo4 cells from Aliexpress. They don't really specify the brand on the listing, but when they showed up, I did a charge and capacity test. I only got 295 Ah :/ (Charged to 3.65v, discharged to 2.5v) I guess that's still good at ~ $76 / Kwh according to 295 Ah. They don't appear to be used cells, no grinding serial numbers, no corrosion, no swelling. Serial number QR code gives no results though online. I am charging a different cell now to do another capacity test.
After asking for a datasheet, I was surprised to get a semi-professional looking one from the seller. (Document attached) Cell manufacturer is Batterotech Corporation Limited out of China. One odd thing I noticed is it specifies nominal capacity as 320 Ah, but then further down it specifies capacity at 25c is => 280 Ah. This seems contradictory. After reaching out to the seller, they clarify that the cells are expected 300 - 320 Ah. (And offered me a 5 USD refund on a 2,200+ USD order for my 295 Ah) It also seems suspicious that they rate these at 80 SOC after 8,000 cycles. (With 300Kgf compression)
I guess I'm worried that these are bad quality and will have bad longevity, I also noticed a couple of the batteries make a very quiet bubbling sound if I tilt them, like there is liquid inside, although no bulging and the vent is intact. All cells came around 3.2v +- 100mv. (SOC was likely <20% as it took forever to charge)
What's everyone's opinion on these? Let it ride with a close eye on them? Should I worry about compressing them with my solar application? (Also, the included bus bars are real copper under plating. + for that)
After asking for a datasheet, I was surprised to get a semi-professional looking one from the seller. (Document attached) Cell manufacturer is Batterotech Corporation Limited out of China. One odd thing I noticed is it specifies nominal capacity as 320 Ah, but then further down it specifies capacity at 25c is => 280 Ah. This seems contradictory. After reaching out to the seller, they clarify that the cells are expected 300 - 320 Ah. (And offered me a 5 USD refund on a 2,200+ USD order for my 295 Ah) It also seems suspicious that they rate these at 80 SOC after 8,000 cycles. (With 300Kgf compression)
I guess I'm worried that these are bad quality and will have bad longevity, I also noticed a couple of the batteries make a very quiet bubbling sound if I tilt them, like there is liquid inside, although no bulging and the vent is intact. All cells came around 3.2v +- 100mv. (SOC was likely <20% as it took forever to charge)
What's everyone's opinion on these? Let it ride with a close eye on them? Should I worry about compressing them with my solar application? (Also, the included bus bars are real copper under plating. + for that)
