Hey everyone, just got my first Lifepo4 battery tonight and put it on a charger to get ready to run a capacity test. I was checking the voltage and in the process toggled the charger a few times... and the battery read 13.6 volts with the charger disconnected and DROPPED to 13.5 when the charger kicked on. Tried it several different ways because I thought I was crazy, and every time it showed higher when not charging. I reconfirmed it 15 minutes later, with 13.54 v during steady state charge, 13.65 v immediately after disconnecting the charger, then 13.55 v when the charger was restarted.
Charger was providing 16.4 amps, which is the max it can do. Battery is a Zooms 100AH. Charger is an Everstart 15 amp charger for car batteries. Measured with a multimeter directly on the studs, not touching the charging clips.
Is this known Lifepo4 behavior? What causes it? Is it related to BMS design? I would suspect the LA charger somehow, but don't see how it could be supplying current while lowering voltage. Am I wrong to think this is extremely weird?
I don't see reason to believe the battery is defective or anything, but I don't understand how the terminal voltage would drop when energy is being actively added to the system.
Charger was providing 16.4 amps, which is the max it can do. Battery is a Zooms 100AH. Charger is an Everstart 15 amp charger for car batteries. Measured with a multimeter directly on the studs, not touching the charging clips.
Is this known Lifepo4 behavior? What causes it? Is it related to BMS design? I would suspect the LA charger somehow, but don't see how it could be supplying current while lowering voltage. Am I wrong to think this is extremely weird?
I don't see reason to believe the battery is defective or anything, but I don't understand how the terminal voltage would drop when energy is being actively added to the system.