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BQ27621-G1: battery selection

Part Number: BQ27621-G1
Other Parts Discussed in Thread: BQ34Z100-G1, BQ35100

Hi team,

Here' an issue from the customer may need your help:

Using a 9-V battery, C2 and C3 are connected directly to VBAT, but VBAT is 0-6V tolerant.

If the customer would like to detect the remaining battery capacity of a 9-V battery, is it okay to use this one? If not, could you help recommend one?


Best Regards,


  • Hello Cherry,

    What is the chemistry of the 9V battery? It is most likely not a 1 cell battery, it probably has multiple cells inside the casing in series. The BQ34Z100-G1 is the impedance track top of stack gauge we support, this is for rechargeable batteries.

    For primary batteries the BQ35100 should be used, but I don't believe we have a chemistry ID for an alkaline 9V battery.


    Wyatt Keller