Is this cell voltage difference bad?

Devin82m

Solar Enthusiast
Joined
Dec 15, 2020
Messages
94
Hey everyone, I finally got my Overkill BMS working right and charging, but notice this voltage difference between cells. Is this acceptable or should I top balance them again? The cells are Fortune 100 ah cells.

Also I don't actively use the pack, will it lose capacity permanently over time if I don't use it but keep it charged? If so, is it months or several years before it loses a large amount of capacity?

Screenshot_20211031-155142_xiaoxiang.jpg
 
Last edited:

Diysolar123

Photon Sorcerer
Joined
Feb 28, 2021
Messages
662
if you have already top balanced them it is now a matter of how close you want the cells to be maintained.
If you have enabled the BMS balance function it will keep things within 100mv or so over time.
Me, well, I like to keep my cells balanced within 10mv so I use an active balancer and turn off the balance function of the BMS.
I float my pack at 27.2v, each cell is 3.40v +/-1mv... The balancer I use seems to always do a good job, is fast, and does not consume much power at all.
 

time2roll

Photon Sorcerer
Joined
Mar 20, 2021
Messages
2,447
If you charge to 14.00 volts max, the battery is ready to go.
Make some notes and check the balance again in 30 days to see if it improves or degrades.
 
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