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BQ40Z60: Firmware Update vs. Golden Image

Charley A.
Intellectual 430 points
Part Number: BQ40Z60
Other Parts Discussed in Thread: BQ40Z50, , GPCRA0, BQSTUDIO

I have a golden image (srec file) that has been used in production now for the past year without any issues. But recently we observed that it is unable to perform well when the cells are significantly imbalanced.   Single Cell Overvoltage faults occur before Charge Termination Taper Current.  

The srec file was created with firmware version 13, which as I understand has a bug which prevents cell balancing.    My question is, is there a way to update to the latest version of firmware while maintaining learning cycle data and other configurations (Ra tables, Qmax, Chem ID, etc..)? 

Also, where can I find information about firmware releases?  Are there firmware release notes that document firmware differences?

  • 0
    TI__Mastermind 34775 points
    Hi Charley,

    You load old srec into bq40z60 then can export a gg.csv file with the DF settings that you later import to the gauge with updated FW or You can also reference this bq40z50 app note.

    www.ti.com/.../slua743.pdf
  • 0 in reply to Damian Lewis
    Intellectual 430 points

    Will this produce an exact copy of the configuration?  There are some parameters that are not included in the gg, such as Chem ID.

  • 0
    Intellectual 430 points

    I have attached the srec file we need to update.

    Thanks,
    Charley

    BATTERY_DF_v1.00.003_(R4_750mA).zip

  • 0 in reply to Charley A.
    TI__Mastermind 34775 points

    Hi Charley,

    Here's the updated srec with latest released FW v0.15...

    BATTERY_DF_v1.00.003_(R4_750mA)_FW_v0.15.srec.zip

  • 0 in reply to Damian Lewis
    Intellectual 430 points

    Thanks Damien, this is very helpful.

  • 0 in reply to Damian Lewis
    Intellectual 430 points

    Hi Damien,

    I set the Balancing Configuration Register to 0x05.  But the Reference Manual says that Update Status = 0x0E is required.  My update status is 0x04.

    I originally generated Qmax and Ra tables from the online Gauging Parameter Calculator (GPC), because the gauge was unable to automatically learn these parameters after many cycles/attempts.

    What can I do to set Update Status?

    Thanks,

    Charley

  • 0 in reply to Charley A.
    TI__Mastermind 34775 points

    Hey Charley,

    The best way is to do an optimization/learning cycle to get Qmax and Ra table updates. Are you willing to try this again?

  • 0 in reply to Damian Lewis
    Intellectual 430 points

    Hi Damien,

    Yes, I can try it again.  Do you have any advice that would improve the chance that it will work?  Also, is the learned state (0x0E) transferable with the golden image?  I saw the Update Status register increment before, but it resets to 0x04 after a power cycle to the gauge.

    This are the steps I used:

    1- Configure the dataflash with appropriate parameters suitable for customer's application; configure pack's chemistry and perform calibration.
    2- Activate impedance track.
    3- Charge the pack to charge termination. VCT status register will be set.
    4- Allow the pack to rest until the REST flag sets (2 hours).
    5- Discharge the pack at a C/10 to C/5 rate to the Termination Voltage.
    6- Allow the pack to rest until the REST flag sets (5 hours). Qmax should update and Update Status should increment to 05.
    7- Fully charge the pack to charge termination.
    8- Allow the pack to rest until the REST flag sets (2 hours).
    9- Discharge the pack at a C/10 to C/5 rate to the Termination Voltage.
    10- Allow the pack to rest until the REST flag sets (5 hours). The Ra table should update and Update Status should increment to 06.

    Thanks,

    Charley

  • 0 in reply to Damian Lewis
    Intellectual 430 points
    Is there a way to force Update Status to be 0x0E?

    The charger is gauging accurately. And in our configuration the bq40z60 is not permanently mated to a battery pack. When a pack is removed and replaced, I don't want cell balancing to stop working because update status gets reset.


    Thanks,
    Charley
  • 0 in reply to Charley A.
    TI__Guru 73830 points
    Charley
    If you use the GPCRA0 tool to find the Ra table and Qmax values for your pack, then you can set Update Status to 06. You can also set it to 0E to allow cell balancing. The risk comes when you update a pack with a golden file and allow cell balancing before Qmax has updated. This can result in cell balancing issues as Qmax does not reflect the new cells. We recommend allowing Qmax to update for the new st of cells and Update Status to increment to 0E, before cell balancing is allowed to engage.

    Tom
  • 0 in reply to ThomasCosby
    Intellectual 430 points

    Thanks, cell balancing is now active according to CB bit in Operation Status.  And I see that cell balance times are now counting down.  But I don't see that the cell voltages are converging.  How can I confirm that balancing is actually happening?  I am using internal balancing since I don't have external cell balancing FETs.

    BATTERY_DF_v1.00.005(R4_750mA_B15).zip

    My new srec file is attached.

  • 0 in reply to Charley A.
    TI__Mastermind 34775 points
    Charley,

    You will have to start logging in bqStudio and plot the cell voltages after a few hours. You have the cell balancing config set to more than 1 hour per mAh, so you can decrease the value to see the quicker changes in the cell balancing, but also consider doing so will increase the heat dissipated.

    Your CB Settings:
    Advanced Charge Algorithm Cell Balancing Config Bal Time/mAh Cell 1 367 s/mAh
    Advanced Charge Algorithm Cell Balancing Config Bal Time/mAh Cell 2-4 514 s/mAh
    Advanced Charge Algorithm Cell Balancing Config Min Start Balance Delta 3 mV
    Advanced Charge Algorithm Cell Balancing Config Relax Balance Interval 18000 s
    Advanced Charge Algorithm Cell Balancing Config Min Rsoc for Balancing 80 %