Hello everyone,


I consult you:
How much should the voltage difference between cells be to know if a battery is good or bad?


I have read that if the value between one of the cells is greater than 0.2 volts, the battery must be discarded because it is already damaged. Can a battery be repaired with that condition?


regards

I wouldn't say the battery with that much of between-cells voltage difference is damaged, or damaged beyond reparation. For sure performing periodical deep discharge and following full charge (perhaps even twice in a row) may cure the issue by the help of a process called balancing. It's mentioned in manual ...

I had one cell in one of my TB48's with a deviation of 1.3v - I carried out a full discharge until the battery switched itself off (100% to 0% without turning off inbetween) and after allowing it to cool down nautrally at room temperature I fully charged the battery back to 100% - the deviation is now 0.04 in storage and 0.09 at 100% - perfectly normal with no cell warnings in my last four flights with it and giving flight times up to 18 minutes. So try that as Matthew advised as it will help. If the deviation is very large though (>2.0) after doing one or two deep discharge recycles/calibrations then you may have a fault and I personally would not risk flying my Inspire 1 with such a battery powering it mid air... However, if the battery is still turning on, charging normally and has no signs of swelling/errors displayed in the app then you can still use it for performing calibrations/checks at home, transforming the drone and using it as a power bank for charging your RC/devices in the field. I just wouldn't fly the drone with it. Hopefully the discharge calibration/s will sort it out though and I suggest only doing them when issues like this arise. Good luck.