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BQ40Z50-DEVICE-FW: Capacity gain update mechanism and how to use it

Part Number: BQ40Z50-DEVICE-FW

Hi,

I would like to ask about the Capacity gain update mechanism and how to use it.

1. What are the renewal criteria for Capacity gain? Our customer found that some battery's Capacity gain was updated to 0.5, while CC gain was not updated and remained in the normal range of around 3, during mass production.

2. From my understanding, CC gain reflects the detection accuracy of the ADC, so CC gain needs to be corrected. However, Capaicity gain is just multiplying CC gain by a fixed coefficient(298261.6178), what role will Capacity play and why can't CC gain be used directly?

Looking forward to your reply, thanks!

  • Hello Kailun,

    Capacity gain and CC gain must be aligned for proper operation of the gauge, the two values are both critical for gauging. Capacity gain is used so the gauge doesn't need to perform as much floating point math, we can just program the capacity gain value is directly so the gauge can easily reference it which saves RAM and power.

    Sincerely,

    Wyatt Keller 

  • Hi Wyatt,

    Thanks for your reply! I understand the significance of Capacity Gain now. Could you please explain why does  the capacity gain change during use? Is there any mechanism or standard that would make it change or automatically correct? Our customer found that some battery's Capacity gain was updated to 0.5, while CC gain was not updated during mass production.

  • Hello Kailun,

    The values should not change in the field, they are set during production programming/calibration.

    Sincerely,

    Wyatt Keller