Quote:
Originally Posted by bronsonj
...... you really don't need anything fancy ........Just something that'll shut off when you want it to as a backup. The BMS should stop the charge where you want it, the charger cutoff is a backup.
|
Bronsonj, you have it the wrong way around. The BMS should be the final, fail safe protection, not the first. The charger should cut off when required, with the BMS only intervening if the charger fails to shut off correctly.
True, you don’t need anything fancy, but you do need more than a constant voltage power supply. You need a constant current (CC) and a constant voltage (CV) power supply.
You set the charge current, say 10A and the maximum voltage, say 57v as in you case, then the charger will start charging in CC mode at 10A until the voltage approaches 57v. Once the current requirements drop below 10A, the charger switches to CV mode and holds the voltage at 57v until the current drops to about 10% or 20% of the CC value, or 1 to 2 amps. The charger should then switch off.
Only if a single cell goes above the preset voltage or if the pack voltage goes above the preset voltage should the BMS intervene and cut charging.
Cheers
Pat.