Comparing the SOC Accuracy Between Battery BMS and Sunsynk Inverter – Which Source Should Be Prioritized?
Hello Sunsynk community,
I am operating a Sunsynk PolyTrack hybrid inverter + lithium battery system with a BMS and have noticed a discrepancy in SOC between the values displayed from the battery BMS and the inverter, especially after deep discharge and fast charging cycles from the PV.
Practical Observations:
The SOC from the battery BMS is usually 5–10% higher/lower than the inverter.
After full charge, the discrepancy decreases but doesn't disappear completely.
There are no BMS communication errors.
I would like to open a discussion on:
In practical operation, should we trust the SOC from the BMS or the inverter?
Does this discrepancy affect the switching logic or battery protection?
Is there a way to better synchronize or calibrate the SOC in a Sunsynk system?
I look forward to receiving shared experiences from systems that have been running stably for a long time or from technicians who have handled similar situations. Thank everyone.