behaviour of multiple BMS in parallel

[max_w101]

I have 3 “ROCK 100” LiFePO4 providing 300ah charged from a DC-DC controller. These batteries have Bluetooth so I am able to connect to each one to see what is going on. What I have noticed is that under normal loads (eg fridge, water pressure etc) only one battery is “discharging”, the rest are not accepting charge (they are already charged) but are also not “contributing”. The battery doing the work is closest in the parallel chain to the terminals (load). Is this normal? Does it also mean I should “rotate” the batteries every now and then to even out the wear?

Also, I assume the other batteries will "come on line" when the voltage falls to some level, but won't this result in a large load flowing to the battery that is "most flat"?

[s/v Jedi]

Originally Posted by max_w101

I have 3 “ROCK 100” LiFePO4 providing 300ah charged from a DC-DC controller. These batteries have Bluetooth so I am able to connect to each one to see what is going on. What I have noticed is that under normal loads (eg fridge, water pressure etc) only one battery is “discharging”, the rest are not accepting charge (they are already charged) but are also not “contributing”. The battery doing the work is closest in the parallel chain to the terminals (load). Is this normal? Does it also mean I should “rotate” the batteries every now and then to even out the wear?

Also, I assume the other batteries will "come on line" when the voltage falls to some level, but won't this result in a large load flowing to the battery that is "most flat"?

No, you have connected them wrong. Search for how to connect batteries in parallel.

[smac999]

with lithuim want to create equal lengh jumpers for each battery. to main bus bars.

but yes the others should start doing work at some point. either more load or lower soc of the 1st batt