Hello everyone.
We have developed a new 8-cell LiFePO4 Battery (180Ah) and we use bq34z100-g1 to monitor it. During last month tests, we had connected two batteries in series and conducted many charging/discharging cycles (0-75%) DOD without having a problem. Having deeply discharged both batteries (SOC<10%) for the first time, one of them (battery B1) seems to calculate SOC as expected. However, the other one (battery B2) estimates battery SOC with a strange pattern.
As shown in figures, both batteries have the same charging/discharging current and their voltage values seem to be the same during the test. SOC positive slope (during charging) seems equal for both batteries. On the other hand, during discharging, as SOC decreases, three different slope values appear in the second battery B2.
The parameters for bq are presented in the Texas Instruments Data Flash File.
SOH value is 100% for both batteries.
Can you please explain this awkward behavior of the bq SOC?
B1 graph:
B2 graph:
Texas Instruments Data Flash File:
