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BQ40Z50-R1: BQ40Z50-R1

Cherry Zhou
Mastermind 22235 points
Part Number: BQ40Z50-R1
Other Parts Discussed in Thread: BQSTUDIO, BQ40Z50

Hi team,

The customer would like to know what is the purpose of the Avg P Last Run, Delta Voltage, Temp a, Temp k, Max Avg I Last Run, Max Avg P Last Run in Gas gathering in BQ40Z50-R1.

When the bulk BMS writes to the SREC file, there are several missed writes that remain at the chip defaults. What is the impact of this and will it cause inaccurate calculation of the electricity?

The SREC file is configured as follows:

The chip defaults as follows:

Could you help resolve this case? Thanks.

Best Regards,

Cherry

  • 0
    TI__Guru 57697 points

    Hello Cherry,

    All the  'last run' parameters are updated by the gauge and track current/power from the last discharge.

    I do not think there were missed writes. I recommend that you read back after the write to verify. These values will be then be updated by the gauge after a discharge. You can verify this.

  • 0 in reply to Shirish
    TI__Mastermind 22235 points

    Hi,

    Thanks for your support!

    Shirish said:
    I recommend that you read back after the write to verify. These values will be then be updated by the gauge after a discharge. You can verify this.

    After write the customer click "read", and found these writes did missed. The srec file used at production is exported from gold sample and is battery-learned. The customer wonders if these items are really not written, what is the bad effect? Will it cause volume of calculations are not accurate? 

    Thanks and Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Guru 57697 points

    Hello Cherry,

    These values are writeable. You can check using bqStudio through the Data Memory tab and try to write each value and read it back.

  • 0 in reply to Shirish
    TI__Mastermind 22235 points

    Hi,

    Thanks for your reply. And the customer would like to clarify what is the impact if these values are not written in volume production? Will it cause inaccuracy in current calculations? Because the srec file used in volume production is a battery-learning file.

    Thanks and Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Mastermind 22235 points

    Hi,

    May I know is there any updates about the question above?

    Thanks and Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Guru 57697 points

    Hello Cherry,

    The first cycle and low temperature operation may have larger error in the first few cycles.

    The bq40z50 will learn these values over time if not written in volume production.

  • 0 in reply to Shirish
    TI__Mastermind 22235 points

    Hi,

    Thanks for you patience!

    A volume produced BMS, which generally does not perform comparable battery learning as golden sample during subsequent use. If those values are not written at the time of volume production and are learned by the BQ40Z50 in subsequent use, will the BQ not be able to display the battery level after learning without a comparison specification? What do these values do?

    Thanks and Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Guru 57697 points

    Hello Cherry,

    The last run max current is used to determine if the battery has enough capacity to power the system without dropping voltage below minimum system voltage. If the battery is >50% charge and the max load is present when the battery is first used, then there should be no problem as the value will get updated.

    The gauge will report RSOC even if these values are not written in production. The accuracy may be slightly worse than if the correct values are written.

  • 0 in reply to Shirish
    TI__Mastermind 22235 points

    Hi,

    Thank you so much!

    Shirish said:
    The accuracy may be slightly worse than if the correct values are written.

    As you mentioned, why the accuracy will be slightly worse than if the correct values are wirtten?

    Thanks and Best Regards,

    Cherry

  • 0 in reply to Cherry Zhou
    TI__Guru 57697 points

    Hello Cherry,

    Since the gauge does not know the actual current, it is possible that it will run a simulation with a different value of current. This can cause a slight error. The gauge will learn the average current and correct itself after that.

  • +1 in reply to Shirish
    TI__Guru 57697 points

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