Hi, thought id try out these active balancers people have been discussing. I have connected up the balance unit to a spare purposely unbalanced 16s 280ah LFP pack and it doesn't appear to be working at all, the run light comes on, on the connectors measure fine with a multi meter but it doesn't balance the pack at all, I have left it on a non used pack at 3.45v per cell with a 70mv difference and its been like for over a week and not changed at all, I can hear the whining noise likes its doing something.
First, you should use a multimeter to measure cell voltage using the same instrument. Measure directly on the balancers ‘sense’ leads so you are measuring exactly the voltages it is seeing.
Since individual channels have +/-5mV accuracy, take actual max - min voltage difference and subtract 10mV for worst-case delta.
Balance current is ~100mA per every 10mV of delta, so if your 70mV delta assumption is correct, the minimum balance current should be ~600mA.
If you have run your balancer for ‘a week’ meaning 168 hours straight. 600mA of balance current would translate to 100.8Ah or 36% of battery capacity, so either you have not been operating it for that length of time on a quiescent battery (no charge current being put in or discharge current being taken out), or it is defective.
I only connect my Heltec active balancer after LVD when the (bottom balanced) battery is discharged and it works exactly as expected.
If you are too-balanced, it should only be connected while the battery is being held in float and disconnected as soon as the battery discharges below that level.
Because these Heltec Balancers are operational throughout he full charge curve, it is important to disconnect them before you discharge below float voltage or they will screw up the balance.
I have a cheap voltage monitor with relay controlling the ON contact on mine so that I can control / program the voltage levels where the balancer is ON…