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Original question:

BQ40Z50-R2: Question Regarding bq40z50 SOC Jumping and Capacity Accuracy

BQ40Z50-R1: How many cycling should a pack take for an accurate rsoc?

joy zhou1
Intellectual 530 points
Part Number: BQ40Z50-R1
Other Parts Discussed in Thread: BQ40Z50

Hi, 

We have a bq40z50-r1 based project, 4s16p, CHEM ID 0x0444, after a pack is programmed with golden .srec file and done proper calibration, before the pack can report a proper rsoc, should it do learning cycling? if it is needed, how many cycling it should take for remaining capacity/rsoc .etc to become accurate?

Please advise.

Thanks,

Joy

  • 0
    TI__Mastermind 24870 points

    Hello Joy,

    The device should go through a learning cycle. Only one cycle for learning should be good. I would recommend doing one more cycle as an accuracy check.

  • 0 in reply to Kang Kang
    Intellectual 530 points

    Hi Kang,

    Thanks a lot for your reply! I will let my customer know this.

    Right now, for the project, after programmed with golden .srec file, on some of packs, it looks like they need 4 to 5 cycle to get an accurate report. What's your opinion why this is happening?

    Please advise further.

    Thanks,

    Joy

  • 0 in reply to joy zhou1
    Intellectual 530 points

    Hi,

    My customer got an issue, they programmed the packs with golden srec file, and they did cycling for the packs, (but I am not sure whether they got cycling successful, got QMAX/Ra table updated before shipment). Currently, some packs couldn't report soc properly in final customer side when the packs wakes up first time. We know bq40z50 can learn and update itself to get accurate soc, and maybe our golden srec file need to be improved for future build. But for the packs which already in final customer side, my customer want to know:

    The next question from our customer is if it’s okay to use these batteries?   When will the fuel gauge become accurate?

    Please help to answer the questions.

    Thanks,

    Joy

  • 0 in reply to joy zhou1
    Intellectual 530 points

    Hi,

    1)I got more info from my customer:

    Yes, all the packs were cycled at our factory.  Sometimes 5 ~ 6 times for the fuel gauge to become more accurate.   These were shipped to our customer. 
    FYI – We have 40+ units that even after 5 ~ 6 cycles the fuel gauge is still not accurate.  These are being held at the factory for future programming.  
    Please help to answer the questions:
    The next question from our customer is if it’s okay to use these batteries?   When will the fuel gauge become accurate?
    2) Another question from my customer:
    Also, at our factory when they prepared our production and then checked some of the batteries before shipping, they discovered the batteries had forgotten their fuel gauging / SOC and had to be cycled again to relearn.   It seems when they go to sleep they forget their capacity.
    Please advise why this is happening, whether this can be avoid and how?
    Thanks,
    Joy
  • 0 in reply to joy zhou1
    TI__Mastermind 24870 points

    Hello Joy,

    Are they running a learning cycle? Can they read out the gg.csv file before and after the first learning cycle? I would like to check the flags and settings.

    The fuel gauge does adapt over cycles.

    The customer can also take the accuracy for 5 to 10 packs after the multiple cycles and average out the Qmax and Ra table and use that as the golden file.

  • 0 in reply to Kang Kang
    Intellectual 530 points

    Hi Kang,

    They did run a learning cycle. But whether it was successful or not, I am not sure. I will ask them to read out the gg.csv before and after the first learning cycle, and send for your checking.

    Right now, the customer understood: the golden srec file maybe need improvement. But they really need to know for the packs which in the final customer side, can they leave them as is, waiting fuel gauge adapt over cycles? And if it is ok, how long or how many cycles it will take?

    Please advise.

    Thanks,

    Joy

  • 0 in reply to joy zhou1
    TI__Mastermind 24870 points

    Hello Joy,

    Please check update status. If it is 0x06 or 0x0E, the learning cycle is successful.