Originally Posted by Flod
Hi the voltages was 3.28 andv3.29 after winter storage
. I have 8 ea 100ah winston cells.
These voltages seem ok.
Did you do an initial top balance before assembling your 12V bank of 200Ah or was this 800Ah?
If not, I guess you probably would have noticed this voltage imbalance during charging
If you did do the initial top balancing, and there was no voltage imbalance during charging before winter then you most likely have a dud cell in group 4.
You can choose to ignore this and let the BMS take care of it.
But if there's no improvement after a few weeks you probably want to go start looking for the culprit.
In this case, one solution involves fully charging them to about 3.70V (till tail current
is less than 1 percent of capacity), then isolate and let them rest for a few hours. The voltage shouldn't drop below about 3.45V on any of them.
Or better yet, charge cell group 3 (known good) as well, in the same way and then compare the open circuit voltage droop with individual cells of group 4.
If there is a dud, it'll show a faster voltage decay for some time after coming off the charger
Anyone else having experience with weeding out a dud cell, may have come up with their own ingenious way?