Good day,
We have succesfully performed a learning cycle using a bq27421-G1A dev board using GDK hardware and battery managment studio software.
It went well according to software, but perfoming a validation run of several charge/ relax/ discharge/ relax cycles, to verifiy compliance of SOC value, we obtained this strange result:
Green line is SOC and as you can see it goes to 99% way sooner than actual full charge as per voltage and current values.
SOC on Discharge seems ok.
I sent log to Gauge parameter calculator to check CHEM ID discrepancy between the one embedded into the gauge chip and the actual one of our cell. Here it is the report we received:
Best chemical ID : 242 Best chemical ID max. deviation, % : 2.56
Summary of all IDs with max. DOD deviation below 3%
Chem ID max DOD error, % Max R deviation, ratio
242 2.56 0.28
257 2.58 0.32
5977 2.78 0.31
5917 2.99 0.23
Max. deviations for best ID is within recommended range. Chosen best chemical ID is suitable for programming the gauge.
Selection of best generic ID for ROM based devices like bq274xx
Device / Family #1
Generic Chem ID Device/ Voltage/ Chemistry max DOD error, %
354 bq27411-G1C: 4.35V LiCoO2 15.93
3142 bq27421-G1D: 4.4V LiCoO2 18.65
128 bq27421-G1A: 4.2V LiCoO2 36.94
312 bq27421-G1B: 4.3V LiCoO2 41.28
Best generic ID 354
Warning: Generic ID Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule
It seems that the A version has an DOD error of 36.94%, while the D version only 18.65%
Is it possibile that chemistry discrepancy could cause such behavior?
Attached you can find validation cycle log file and data memory export.
validation.log4336.data_memory.gg.csv
Thanks and best regards
Matteo