Hi all,
I've recently gotten 6 new batteries to expand by battery bank, one of them was severely out of balance.
I of course, first pre-charged all the batteries and let them balance for a night. Next day without verifying everything was fully balanced i deployed them into the setup.
The first discharge cycle that day caused a under voltage pre alarm while the SoC of the bank was 44%.
The voltages of this battery were
I immediately started a full charge cycle on the whole bank and let it balance for 2 more hours as the bank afterward returned to float and that is too low voltage for cell balancing to continue.
This did not make any significant progress on the cells, so I decided to take this one out of the battery bank to manually charge and balance. The maximum charge current was set to 8A
This is how the cells looked after reaching the absorption phase
This was a couple of hours later, progress, although it being slow.
2 and half days later, it looked like this
4 days later from start, pretty good.
But this is where we are getting stuck. 5 days later (so 9 days from start). Not much progress (for 5 days difference at least)
Any recommendations? Or should I try and do a full cycle on this battery. Is it normal that these batteries can come this imbalanced? I did, of course, update all to the latest firmware.