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Charging strangeness

NMNeil

Solar Enthusiast
Joined
Mar 14, 2020
Messages
443
I received my 32, 100Ah no brand cells and connected the cells in pairs to give a single 200Ah cell. Top balanced, then wired them in series for 48 volts. Hooked up the Overkill BMS and all seemed to be good and they all started at 3.33 volts, then very quickly (5 minutes) one cell rose to 3.65 volts and the BMS started to bleed off voltage. All the other pairs were slowly rising to around 3.4 volts. Charging current was only about 5-10 amps.
I took out and separated the suspect pair of cells and they both showed 3.41 volts, but all the other cells only showed 3.34.
To have 2 bad cells is unlikely, so any ideas what may be the problem?
 
Please ignore.
I took the time to read other posts to find out that I'm not actually top balancing.
Time to buy a charger.
 
I received my 32, 100Ah no brand cells and connected the cells in pairs to give a single 200Ah cell. Top balanced, then wired them in series for 48 volts. Hooked up the Overkill BMS and all seemed to be good and they all started at 3.33 volts, then very quickly (5 minutes) one cell rose to 3.65 volts and the BMS started to bleed off voltage. All the other pairs were slowly rising to around 3.4 volts. Charging current was only about 5-10 amps.
I took out and separated the suspect pair of cells and they both showed 3.41 volts, but all the other cells only showed 3.34.
To have 2 bad cells is unlikely, so any ideas what may be the problem?
If they started at 3.33v, you didn't top balance. Never mind, please ignore me as well.
 
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