I have a 600ah bank consisting of 32 300ah lifepo4 batteries; 2 banks in parallel.
Charge Controller stop at 56.3 volts so individual battery voltage is at around 3.51 fully charge and then the next day 52.9/3.31 and the SOC% will be 100%
My inverter is set to disconnect from the batteries at 49.6 volts, Individual batteries at 3.1 volts; SOC% should read 0%/empty.
So, what happens is after a day of charging and in the morning the batteries will drop down to 49.6 and the inverter will disconnect and individual batteries will be 3.07 to 3.10 volts and the SOC% will be at like 35% and it should be 0%.
I will change it manually and it just gets off again and again. It like the voltages do not match the current amphere hours of the battery.
Can anyone tell me how to fix this and try to keep this SOC% at a reliable reading.
Hey Jeff
I’ll try and assist here, based on my understanding of the BMS logic.
First off, have you set the Nominal Capacity? (Hardware\Shunt\Nominal Capacity.)
Second I suspect the BMS may calculate full capacity based on the cells discharging down to the default Critical low voltage of 2.5V. In which case 35% may sound about right, though I don’t think there’s much capacity left below 2.9V…
You could try changing the Lo Cell Volt (CV1) to 3.0 and see what that does to the SoC?
Or you could adjust your thinking and recognise that for your reasons (eg battery life?) you wish to only discharge to 35% and you 600Ah battery pack gives you a usable 390Ah.
I may be wrong with this train of thought, and if so I’ll happily be corrected by anyone with more experience. Or if this is correct then a little afirmation would be nice
