48V battery charger question

[Simpleone71]

I bought a BigBattery 48v blue charger that outputs 57.6v DC / 20A to do an initial charge on 6 EG4 LL-S batteries to get them at the same SOC. I see now that the charger states it is exclusively for two BigBattery models of their LiFePO4 batteries. In the manual of the EG4 LL-S batteries, their recommended settings to charge are 56.2v (+/-0.2v) and the BMS module protection is at 60v charging.

Would it be ok to use this charger to top off the EG4 batteries or not? Being new, I was not sure since it does output a higher charging voltage.

 

[BentleyJ]

57.6V is 3.6V per cell for a 16S pack. While this voltage is within the safe operating range of LFP chemistry it is very close to the typical Over Voltage Protection Limit of 3.65V which many BMS are set at.

You can use the charger but it may trigger an OVP event unless the cells are very well balanced.

 

[hwy17]

Yes it should be fine. Like Bentley says these no settings charges use slightly high voltages, but I would bet this charger is going to float at 55.2 or less like the old EG4 model. Fine for using one off once in a while, maybe not something you'd want to charge with every day.

After you charge them all too 100, give the last one a few hours to rest off the charger before you parallel them, if you don't want the rest to suck a few percent out of it.

 

[Simpleone71]

Thanks everyone. Yes, this will be a one-time thing to get them all to the same SOC. They are brand new, so I hope they are close. Moving forward, they will be charged by a Victron MPPT or Victron Multiplus II.