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BQ27421-G1: Remaining Capacity during CFGUPMODE

Part Number: BQ27421-G1

Dear Support team,

It turned out that when CFGUPMODE is True, the value of Remaining Capacity is considerably different from the ideal value.
Could you let me confirm below things.

1. Is there a possibility that Remaining Capacity will not be counted normally in the situation where the write command is not issued and the Standard Command is read only during CFGUPMODE?

2. Is it possible that the SEALED / UNSEAL status affects the Remaining Capacity calculation regardless CFGUPMODE conditions?

3. Please let me know if there is any other possibility that Remaining Capacity may not be calculated / integrated normally.

Best Regards,
Hirokazu Takahashi

  • Hello Takahashi-san,

    In the TRM section 2.4.3 CONFIG UPDATE Mode

    It says: In this mode, fuel gauging is suspended while the host uses the extended data commands to modify the configuration data blocks. To resume fuel gauging, the host sends a Control() SOFT_RESET, EXIT_CFGUPMODE, or EXIT_RESIM subcommand to exit the CONFIG UPDATE mode which clears both Flags() [ITPOR] and [CFGUPMODE] bits.

    The fuel gauging is suspended in the CFGUPMODE, I'm not sure what the registers are filled with, but there will be no accurate gauging while in that mode.

    Sincerely,

    Wyatt Keller

  • Hello Wyatt-san

    Thanks for your prompt reply.
    Could you please answer for my question #2 and #3 at previous post also?

    Best Regards,
    Hirokazu Takahashi

  • Hello Takahashi-san,

    SEALED or UNSEALED mode will not affect the calculations done by the gauge.

    The remaining capacity is based on the programmed configuration from the user and the chem ID, so if the incorrect data for the battery is uploaded it will not be calculated accurately. Or if the gauge isn't performing the algorithm, like when it is in the CFGUPDATE mode.

    Sincerely,

    Wyatt Keller

  • Hello Wyatt-san,

    Is there any mode other than CFGUPDATE mode where the gauge is not performing the algorithm?

    Best regards,

    Suzuki

  • Hello Takahashi-san,

    Yes, the gauge must also know the battery is inserted, if it thinks there's no battery the IT algorithm will not run. Check in the TRM: 4.1.7 BAT_INSERT: 0x000C

    Sincerely,

    Wyatt Keller