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BQ34Z100EVM: See above

Luke Adams
Prodigy 20 points
Part Number: BQ34Z100EVM
Other Parts Discussed in Thread: BQ34Z100, GPCCHEM

Tool/software:

Hi,

We have been testing the fuel gauge (BQ34Z100 evaluation board) by leaving it connected to a battery (6-cell NiMH D) for a period of time and have noticed that the fuel gauge report for the remaining capacity is not accurate anymore.

The main issue is that after sitting on the shelf for 6 months.  Should it be able to track self-discharge of the battery?

Do you have data on long term storage with this fuel gauge?
How can we rectify this issue?
Should the fuel gauge be able to cope with a battery that is stored on the self for up to 6 months?
On another note we need help with the programming and learning cycle.  Are we using the optimum profile/program for our battery?
Luke
  • 0
    TI__Mastermind 27405 points

    Hello Luke,

    This question has been assigned and will be followed up as soon as possible.

    Thank you,
    Alan

  • 0 in reply to Alan Frias
    TI__Mastermind 26875 points

    Hi Luke,

    1 Is the device powered off?

    2 no

    3 after 2 ocv measurements have been taken your device should be estimating SOC accurately.

    4 If the device is being powered on

    5 This should be done before deploying your battery fuel gauge to the field. You will need a chemid match using the gpcchem tool and complete a learning cycle both linked below. 

    GPCCHEM Application software & framework | TI.com

    Achieving The Successful Learning Cycle

    Regards,

    Diego

  • 0 in reply to Diego
    Prodigy 20 points

    Sorry I am struggling to see what your comments refer to, could you please elaborate?  How do your comments refer to my original comments?

    1.The main issue is that after sitting on the shelf for 6 months. Yes device is powered off.  

    2.Should it be able to track self-discharge of the battery? Are you saying that it cannot track or estimate self discharge?

    How do I perform an OCV measurement? - After 2 ocv measurements have been taken your device should be estimating SOC accurately.
    Thanks
    Luke
  • 0 in reply to Luke Adams
    TI__Mastermind 26875 points

    Hi Luke,

    1) No, the device will not track SOC if it is powered off, after powering on the gauge OCV measurements are required before gauging is accurate.

    2) The gauge can track the discharge, given that the discharge current is above the quit current threshold and the device is powered on.

    The first OCV Measurment is forced once the gauge is powered on, the second one can occur when the battery is in a relaxed state. 

    Regards,

    Diego

  • 0 in reply to Diego
    Prodigy 20 points

    Thanks for clearing this up.  The Fuel gauge is left connected to the battery so in an ON state.

    So does the second OCV measurement happen automatically?

    Have tests been done to track self discharge over long periods i.e. 6 months?

    How would you suggest that inaccuracies whilst inactive are resolved.  Is there a process that can be performed?

    Luke

  • 0 in reply to Luke Adams
    TI__Mastermind 27405 points

    Hello Luke,

    We have received your update and working on your response.

    Thank you,
    Alan

  • 0 in reply to Alan Frias
    TI__Mastermind 26875 points

    Hi Luke,

    Yes, the second OCV measurement will happen automatically when the battery enters a relaxed state.

    Yes, if the gauge is powered on it will track SOC. It is important to note that the gauge will need to be in discharge mode.

    The gauge will correct SOC after 2 ocv readings, these typically will occur rather quickly with normal operation.

    Regards,

    Diego

  • 0 in reply to Diego
    Prodigy 20 points

    Thanks, so do you have any data on how the gauge works over a long period with the gauge powered on but the battery not being discharged?

    Also, if we were to move the fuel gauge to work on a different battery, what is required, is there a process that needs to be followed? 

  • 0 in reply to Luke Adams
    TI__Mastermind 27405 points

    Hello Luke,

    We have received your update and due to a back log of the queue we ask for some more time until we send a response.

    Thank you,
    Alan

  • 0 in reply to Alan Frias
    TI__Mastermind 26875 points

    Hi Luke,

    Unfortunately, we do not have this data. 

    If you were to move to a different battery you would need to develop a new golden image for the new battery used.

    Regards,

    Diego