[Solved] FCC issue in Dell batteries
Usually I get Dell batteries with 100 or less cycles wich show very low learned capacity, lets say less than 10% , which for the number of cycles seems too low. If I change FCC in NLBA (or better in EV2300 under "learned capacity" item, I can charge faster the battery and make a calibration cycle.
What happens is that injected capacity and real capacity is much higher than learned capacity, but in spite of these values after every calibration cycle capacity gets down, why does this happen, does calibration cycle take other values like internal resistance?
Attach the charge/discharge log.
This is a common issue with Dell batteries.
EMF/EDV values in firmware are set too high because manufacturers state that the cells that they use in the battery become unstable and there is a very high voltage drop if discharged below 3.6-3.5v
As can be seen in the log the chip will readjust SOC and FCC when cells have reached around 3.6v.
If log is inspected until the end it can be seen there there is no cells instability and no sudden voltage drop. Of course there is some imbalance but it's considered normal for used cells.
The EMF/EDV set from factory corresponds very well to cells voltage curve but only when they are new and have very low IR, but as the cells age and IR increases these values become incorrect.
The solution is to lower the values using BQStudio.
It should be ok.
Run another calibration cycle and post the log.
Further adjustments can be done if needed.
FCC was increased but not a lot. FCC increase by cycles will depend on how chip is programmed.
Lower EMF to 3.5v and set FCC to 4000mah.
After this do final calibration cycle to confirm everything is ok.