Hello everyone,
I have a WattCycle 48V 100Ah LiFePO4 battery (16S) connected to a Victron MultiPlus-II GX system with SmartSolar MPPT chargers and a SmartShunt.
I am experiencing a persistent problem with the BMS SOC calibration.
The Victron SmartShunt indicates 100% SOC, while the WattCycle BMS reports only 84%. In the past, the BMS has even displayed SOC values as low as 1% despite the battery voltage being above 53V.
During our latest charging test:
Battery voltage: 56.4V
Highest cell voltage: 3.555V
Lowest cell voltage: 3.486V
Cell voltage difference: 69mV
Charging current: 0.8A
BMS SOC: 84%
Charge MOS: ON
Balancing status: Active
BMS firmware: WT1002_10016x2_0518
We have already tested an absorption voltage of 56.8V without successful SOC synchronization.
WattCycle support has recommended absorption voltages ranging from 57.6V up to 58.4V, with a 2-hour absorption period. However, I am concerned about individual cell overvoltage, especially since the highest cell already reached 3.555V.
My questions:
Has anyone experienced a similar SOC calibration problem with a WattCycle 48V battery?
Has anyone successfully synchronized the BMS SOC to 100%? If so, what charging settings or procedure worked?
Does anyone know the exact SOC synchronization conditions for this BMS firmware?
Does this battery use active or passive cell balancing?
I would greatly appreciate any practical experience or technical information.
I have attached two screenshots showing the BMS readings and individual cell voltages during charging.
Thank you for your help!
Richard
