My LFP40 cell voltages on my XM3500 are drifting apart, as expected without a BMS.
The highest cell is 3.89v after charger cutoff, and the lowest cell is at 3.29v, and I want to bring the low ones up using a CV/CC supply, but have never done this, so thought I'd ask for detailed guidance to avoid smoke. The manual is pretty sparse and not much help for me.
The supply is a Mastech 0-60V, 0-6A
From the manual:
"For constant voltage mode turn Current controls full CW(Max), switch on power supply and adjust to desired Voltage, Connect load to output terminals"
OK, easy enough...
For a battery at 3.3V for instance, what voltage do I set the Power Supply to? 100mv over battery? 50mv? Then just keep bumping it up until I reach my goal of 3.7V?
Or do I set output to my goal voltage of 3.7V and limit current to X Amps?
I'm building my version of Jans Darlington/LED simple BMS today for basic cell protection, but want to get all my cells above 3.7V before connecting it up, as that seems to be where the BMS takes cells with voltages higher than this.
I suppose these low cells will just drop below 3.7v again, but that's another issue, and maybe not if I always keep SOC higher than I have.