EVE 280Ah: got old cells?

[kgol]

First of, I hope I'm posting in the correct category. If not, sorry for the inconvenience. First post on this forum I did some searching but couldn't find a similar topic.

I got some Eve 280 Ah cells from Alibaba from a seller with a good reputation. These cells were sold as "new" and "grade A". Their production date codes start with a "9". Based on a post in another forum (https://secondlifestorage.com/index.php?threads/eve-280ah-lifepo4-review-dongguan-lightning-new-energy-technology.10271/#post-70901), I understand that these cells were produced in 2019?

So I have a few questions that I was hoping some of you might be able to help me with
- Is my decoding correct and are these indeed cells from 2019?
- They are currently around 30 % SOC and their voltages are within 12 mV. I thus do not expect that much (calendar) degradation will have occurred?
- Should I expect problems?
- Anyone else with a similar experience?

All comments welcome.

 

[snoobler]

Welcome to the forum.

First of, I hope I'm posting in the correct category. If not, sorry for the inconvenience. First post on this forum I did some searching but couldn't find a similar topic.

I got some Eve 280 Ah cells from Alibaba from a seller with a good reputation. These cells were sold as "new" and "grade A". Their production date codes start with a "9". Based on a post in another forum (https://secondlifestorage.com/index.php?threads/eve-280ah-lifepo4-review-dongguan-lightning-new-energy-technology.10271/#post-70901), I understand that these cells were produced in 2019?

So I have a few questions that I was hoping some of you might be able to help me with
- Is my decoding correct and are these indeed cells from 2019?

Unknown

- They are currently around 30 % SOC and their voltages are within 12 mV. I thus do not expect that much (calendar) degradation will have occurred?

30% established by voltage? If so, that's not reliable. 30-70% is pretty difficult to pin down by voltage. Should expect little to no degradation.

- Should I expect problems?

Based solely on voltage? Inconclusive. Confirm IR with impedance tester and test cells for capacity. Once you've establish conformance with the data sheet, you can gain confidence.

 

[kgol]

30% established by voltage? If so, that's not reliable. 30-70% is pretty difficult to pin down by voltage. Should expect little to no degradation.

You're right, the 30 % is indeed more of a guess based on the voltage I measured. My multimeter showed 3.25 V.

 

[snoobler]

You're right, the 30 % is indeed more of a guess based on the voltage I measured. My multimeter showed 3.25 V.

Might be a good guess. It seems most recently shipped ones measure 3.28-3.30 at very nearly 50%. I actually tested mine upon receipt to see their retained capacity, and they were darn close to 50%.

 

[kgol]

(reply to own question)

Found a previous thread: https://diysolarforum.com/threads/lishen-272ah-thread.12871/page-14.
Apparently this is rather common, and the cells appear to be perfectly fine.