I think I found my bouncing problem on BMS voltage that happen as voltage increasesI think I found my bouncing problem on BMS voltage that happen as voltage increases, I upgraded my BMS boards and controller to v4.4 because of voltage variations during the day, looks like it is an interference problem from a Chinese load resistor that starts to burn off current at a set voltage to suit my lifepo4, as the voltage gets to a set point this load resistor bank starts to flash on there leds ( one per bank ) indicating the burning off energy as the voltage rises, the leds stays fully on showing a higher current of burning off extra energy at a higher set point of voltage, I had a brain storm thinking that this might be the cause of the bouncing voltage readout from the diyBMS, so today I unplug the load resistor bank and the voltage bouncing went away, time will tell over the next few days
With all of those modules stacked tightly together you may want to consider adding heat sinks and a fan to improve the cooling aspects. If/when they enter bypass mode they will generate considerable amounts of heat (the same as the yellow boxed resistor bank does).
Which temperature probe are you using and do they connect to the modules?
I have disconnected the resister bank, It may never get used again, I have set the by pass temp to 55 degs, the Ext temp probe on the PCB only rises a few degs above normal when in by pass so it gives me a good induction of how well the board handles the closeness to each other
The load resistor was not the problem, the same thing happened today, looking at the data on my MQTT, at 2:15pm the cells 0_0 to 0_4 of the 16 cells all started to voltage bounce and all within 10 secs, cell 0_4 dropped in voltage over a period of 3 hours where the rest of that group flat lined or increased in voltage
Then at 3:15pm with 50 secs the cells 0_5 to 0_15 started the voltage bounce, I did notice the second group of cells, cell 0_6 dropped in voltage over a period of 3 hours where the rest of that group flat lined or increased in voltage, this all continued until I got home and power cycled each cell which was after dark, very strange what is happening and usual that they went in a group order.
The voltage set point for balancing is set to 3600mv, now out of each group this coincided then one of the cells reached that 3600mv, luckily I caught this early and didn’t continue over night bouncing and draining current at the same time from the PCB.
Tomorrow I have set the balancing voltage cut at 3700mv and see if it doesn’t start bouncing again
06 voltage drop
04 voltage drop
The whole event
The 2 set points that balancing started and bouncing points