I have a relatively new (3 month old) house battery system with six 300AH NG 24V batteries arranged in two “banks” of three batteries, each with a separate NG 1000A BMS. The system also includes an Ekrano which is controlling a pair of Quatro inverter/chargers using DVCC.
The system works great, except that the two banks seem to diverge in their state of charge and “settle” at between 10% and 11% difference in state of charge. Currently, one of the BMSs says it’s bank is at 86.5%, while the other one says the bank is at 97.8%. The battery voltage is the same within 1 mv (28V vs. 27.99V). The batteries are not taking any significant charge (less than 1 A).
Everything works fine, but the fact that the two banks are this much different leave some ambiguity as to how much capacity the system actually has. The Ekrano averages the two and says the bank is 92.1% state of charge.
Is there something I can do in terms of calibration that would help balance the two banks better? I suspect that they are actually better balanced than the BMSs say they are.
Suggestions?