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BQ20Z70-V160: FCC abnormal

Part Number: BQ20Z70-V160

Hello Sir:

Please refer our issue as below processing.

1. send shutdown command 0x0010

2. charge wake up (150mA)

3. after wake up, check remaining capacity and full charge capacity parameters are abnormal.

We update screen video record and our gg file for you reference.

Looking forward your feedback.

Thanks a lot.

RTC1200-20230106.zip

  • Hello Statham,

    Does this happen with all units or only some units? If you re-upload the .senc/.srec file does it resolve the issue?

    Sincerely,

    Wyatt Keller

  • Hello Keller:

    No, we did the reupload process, it's cannot fix it.

    Before this issue happened, customer used difference threshold on shutdown voltage and CUV. (I do not know the actual parameter of these thresholds)

    Above settings which had been mass production for a long time, several years.

    Around 2022 end, customer changed the shutdown voltage and CUV with the same threshold, 3.0V/cell.

    Until now, customer got this issue.

    Do you have idea?

    Looking forward your feedback.

    Thanks a lot. 

  • Hello Statham,

    So re-uploading the .senc does not resolve the issue but when they configure the parameters a certain way (CUV = shutdown voltage = 3v) this issue starts to occur when it didn't before?

    I'm not sure why the gauge is reporting RemCap and FCC like this, it should be calculated based on a simulation, try sending a reset command after wakeup if the values are abnormal to induce another simulation.

    Sincerely,

    Wyatt Keller

  • Hello Keller:

    Sorry, I need to update the right shutdown voltage threshold for you.

    The original setting shutdown voltage was 1.75V/cell, and CUV was 2.9V/cell

    After changing the shutdown voltage=CUV= 2.9V/cell, then which abnormal condition happened.

    Is there any reason why the shutdown voltage and CUV cannot be set to the same threshold?

    We can try reset method to work around, but we need to explanation because which has over 50 products had this issues at customer side.

    Please try to give us some reasons on it.

    Looking forward your feedback.

    Thanks a lot. 

  • Hello Statham,

    Do to the age of the device I cannot review the intricacies of the firmware to determine root cause. From what you have provided it sounds that if CUV != shutdown voltage the issue does not occur, and a reset command will most likely clear the issue.

    Sincerely,

    Wyatt Keller

  • Hello Keller:

    Understood your difficulties.

    We try to work around and let battery pack become normal.

    We sent 0x21 to enable IT, then the capacity becomes normal, please refer below vedio.

    Do you agree this way to recovery gauge?

    Any side effect on this way?

    Please kindly provide your recommendations on it.

    Thanks a lot.

  • Hello Statham,

    Toggling the IT enable command will trigger a new simulation of FCC and RemCap, that is also a viable solution.

    Sincerely,

    Wyatt Keller