I have two 8.2kWh batteries with an AC3.0 inverter. The second battery is about 7 months younger than the first. Often the LEDs on the batteries are out of step - today for example I have 3 on the first and 2 on the younger one. The SOC at the time was 56%. It was similar first thing (2 and 1 LEDs) at 25%.
Should I be concerned?
The system is working fine.
The batteries rarely, IMHO, charge or discharge at the same rate. I have 2 X 8.2s and there is always a difference in the rates, with the primary one charging and discharging faster.
gwynnej3 long as their voltages are the same you don't need to worry.
thewhalw21 they’re wired in parallel so surely they can’t help but be the same?
gwynnej3 They are not the same - a great part of the BMS resposibility is managing cell voltages to keep things in balance. Not only could your overall voltage of each of your battery 'boxes' be different but individual cell volages within the batteries may be different.
I shalln't worry about it then! Thanks
Yeah, absolutely none of that happens in my twin 8.2s. And yet the indicated SoC varies wildly. In fact, I've seen the biggest SoC difference and biggest SoC jump under 3013. The performance has gotten demonstrably worse.