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BQ27441-G1: Maximum Design capacity

Liam Maskey
Prodigy 50 points
Part Number: BQ27441-G1
Other Parts Discussed in Thread: BQ27Z561-R2, GPCCHEM

Tool/software:

Hi,

From the data sheet the BQ27441-G1A has a maximum design capacity of 8000mAH. A project I am working on uses a battery of 10000mAH. Is there a work around so that I can use the BQ27441-G1A to monitor a 10000mAH battery?

Thanks,

Liam

  • 0
    TI__Mastermind 26395 points

    Hello Liam,

    Since you are waiting to use the battery gauges that have pre-programmed chemID you can't use a battery cell that is above 8000mAh, the easiest solution would be to go to a BQ27Z561-R2 that has the ability to use all the entire chemID library.

    Thank you,
    Alan

  • +1 in reply to Alan Frias
    Prodigy 50 points

    Hi Alan

    The design I am working on already incorporates the BQ27441-G1A in the hardware. A lower battery capacity was originally used in the system which was then upgraded to 10000mAh. If there was some other workaround other than having to respin the PCB to accommodate the BQ27Z561-R2 that would be the preferred option.

    The system firmware is able to update the Design Capacity and Design energy for the 10000mAh battery but the %SOC calculations are not accurate and after the 60% SOC point they are very inaccurate. For example with 360mAh transferred from the battery to the load the battery capacity as reported by the  BQ27441-G1A falls by around 1384mAh and the %SOC drops from 60% to 45%

    If there are some other settings in the BQ27441-G1A that I could use to improve this accuracy I would appreciate knowing about then.

    Thanks,

    Liam

  • 0 in reply to Liam Maskey
    TI__Mastermind 26395 points

    Hello Liam, 

    The first step to see if this is workable within your system is to run the new 10000mAh cell through the GPCCHEM tool and see what is the error % difference from your cell to the available chemID's on the BQ27441-G1A. If the % error difference is less than 3% (5% can be workable) than I would have to have a discussion with the team internally to see about next steps. Regardless if it meets this it would still not be super accurate as advertise and would need to be understood for this gauge with the improper cell match. However if the % error is too great than it would force a new battery gauge would need to be used.

    GPCCHEM:
    https://www.ti.com/tool/GPCCHEM

    Thank you,
    Alan