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BQ20Z45-R1_BQEASY-SW: The chip sees half of the declared capacity.

Part Number: BQ20Z45-R1
Other Parts Discussed in Thread: BQ40Z50


Please help.

I'm having trouble estimating the capacity of the battery pack by chip.

Given the values of 5200 mAh, the bq20z45 chip recognizes only half of this value after learning.

The same packet connected to the bq40z50 chip is recognized correctly.

I'm sending a file for analysis with the settings for bq20z45.

The package includes 6 Sony cells US18650VTC5 2600mAh cells (ID Chem 2056)



Pawel Czezyk

  • You need to set Qmax for all cells:

    From you file:

    Qmax Cell 0 = 2581
    Qmax Cell 1 = 2599
    Qmax Cell 2 = 2695
    Qmax Cell 3 = 5200
    Qmax Pack = 2581

    Set all of these values to the same value as Design Capacity (5200 mAh) to start with.

  • Hi

    Thank you for your quick reply.

    I did as you said, but it didn't change anything.

    Only the SOC was stupid.

    I think I've found the cause of the problem.

    The value of the current actually consumed by 2A was different from the value given by the 1A chip.

    After performing the calibration and changing the value in Qmax, the chip started to correctly indicate the capacity.


    Pawel Czezyk