nelsonjrgomes
New Member
Hello,
I've bought 2 x 100 Ah 48V server rack batteries from an Aliexpress seller, to pair with my Growatt SPH Hybrid Inverter. The batteries BMS communicates with my inverter. They are connected in parallel (not yet through a positive and negative bus bar, but that is going to be done in the next few days)
The batteries are working (I have them for about one month), but they are unballanced - when charging, near the top, there are cells whose voltage exceeds 3.7 and the BMS enters safe mode (or whatever is called) - and tries to balance the cells, only resuming normal function when every cell is under 3,4 volts. Unfortunately, I can't define, in my inverter, a max SOC percentage to try and avoid triggering OV protection - the inverter will always try to charge them to 100%, as long as I have excess production in pv.
I've read over here, in the forum, that I have two options - disassemble each battery, top balance cells individually and then reassemble (the hard way); or try to charge slowly each battery, and wait that the BMS with it's internal (passive) balance manages to do what is intended - top balance each battery.
I was thinking in charging each battery, through inverter, to about 95 or 97%, and then, as I don't have a battery charger (besides my hybrid inverter), I was thinking about buying a lab power supply that manages 60 v 5 A to charge the battery slowly (like 3 amps, 56 volts total).
Does this make sense - using the lab power supply to charge the battery? This way, if it doesn't solve the problem, I could use that same lab power supply to individually top balance the batteries.
Thanks in advance,
Nelson
- can I use it to charge the battery to
I've bought 2 x 100 Ah 48V server rack batteries from an Aliexpress seller, to pair with my Growatt SPH Hybrid Inverter. The batteries BMS communicates with my inverter. They are connected in parallel (not yet through a positive and negative bus bar, but that is going to be done in the next few days)
The batteries are working (I have them for about one month), but they are unballanced - when charging, near the top, there are cells whose voltage exceeds 3.7 and the BMS enters safe mode (or whatever is called) - and tries to balance the cells, only resuming normal function when every cell is under 3,4 volts. Unfortunately, I can't define, in my inverter, a max SOC percentage to try and avoid triggering OV protection - the inverter will always try to charge them to 100%, as long as I have excess production in pv.
I've read over here, in the forum, that I have two options - disassemble each battery, top balance cells individually and then reassemble (the hard way); or try to charge slowly each battery, and wait that the BMS with it's internal (passive) balance manages to do what is intended - top balance each battery.
I was thinking in charging each battery, through inverter, to about 95 or 97%, and then, as I don't have a battery charger (besides my hybrid inverter), I was thinking about buying a lab power supply that manages 60 v 5 A to charge the battery slowly (like 3 amps, 56 volts total).
Does this make sense - using the lab power supply to charge the battery? This way, if it doesn't solve the problem, I could use that same lab power supply to individually top balance the batteries.
Thanks in advance,
Nelson
- can I use it to charge the battery to