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BQ27Z561: Battery capacity goes upto 96% only

Part Number: BQ27Z561
Other Parts Discussed in Thread: BQ25601

Hi,

I am using a bq27z561 gauge IC for monitoring the battery. In few instances we have observed that the battery capacity reaches only up to 96% when charging the battery from completely discharged state. However if we reset the fuel gauge using software command, then the capacity corrects itself and reaches 100%

In normal case where we charge the battery from 20-30%, the capacity reaches 100% every time.

Need help in understanding which parameter is incorrectly set in fuel gauge that is causing this issue

  • Hello,

    If you send a reset command the gauge will take an OCV (assumed to be rested voltage) and correlate that to a SOC value. If you just charged your battery and it did not rest the voltage will e higher and the gauge will think the battery is more charged than it is.

    You should only send a full reset command when the voltage is rested.

    Sincerely,

    Wyatt Keller

  • Hi Wyatt,

    I don't want to issue a reset command after full charge. The fuel gauge should automatically show 100% capacity when the charging is complete. The problem we are facing is that when the battery charger says battery is full, at that instance the fuel gauge shows only 97%. And this issue is observed only when we charge the battery from fully discharged state. This means there is some issue with the fuel gauge configurations.

    FYI. The battery is charged using a BQ25601 battery charger IC and charging stops when current is below taper current set in battery charger.

    Regards,

    Jiju Chacko

  • Hi Jiju,

    Does the gauge show 100% after allowing battery to rest? 

    Best regards,