• State Resolved
  • Locked Locked
  • Replies 9 replies
  • Answers 4 answers
  • Subscribers 63 subscribers
  • Views 1047 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ34Z100-G1: current scaling and thresholds

user5014632
Intellectual 515 points
Part Number: BQ34Z100-G1
Other Parts Discussed in Thread: BQSTUDIO

Hi,

Does the following parameters have to be scaled according to the current scaling?

  • Res Current;
  • Dsg Current Threshold;
  • Chg Current Threshold;
  • Quit Current.

For example I have current scale of 4, a 4A current is calibrated to be seen as 1A by the gauge. Shall I divide the standard values of above parameters by 4 also?

Bonus question: My expected End of Charge current is 168mA, which leads to a taper current of 42 with the aforementioned scaling. FC set is -1 to use the full charge detection algorithm depicted in paragraph 7.3.11 1) of the datasheet. Is a Chg Current Threshold set to 40 is low enough to ensure the gauge will have sufficient time to set FC?

Best regards,

Jérémie

  • 0
    TI__Mastermind 34775 points

    Hello Jeremie,

    user5014632 said:
    Does the following parameters have to be scaled according to the current scaling?

    Yes all parameters with mA, mAh, mWh, cWh should be scaled

    user5014632 said:
    For example I have current scale of 4, a 4A current is calibrated to be seen as 1A by the gauge. Shall I divide the standard values of above parameters by 4 also?

    Yes

    user5014632 said:
    Bonus question: My expected End of Charge current is 168mA, which leads to a taper current of 42 with the aforementioned scaling. FC set is -1 to use the full charge detection algorithm depicted in paragraph 7.3.11 1) of the datasheet. Is a Chg Current Threshold set to 40 is low enough to ensure the gauge will have sufficient time to set FC?

    Is that 40mA before or after scaling. If it's before scaling then the new value would be 10mA after scaling which is sufficient for staying in CHG mode when charge termination is occuring.

  • 0 in reply to Damian Lewis
    Intellectual 515 points

    Hi Damian,

    Thank you for your quick answer. I plan to use a Chg Current Threshold of 40 after scaling, i.e. 160mA in reality. There is only a 8 mA margin with the expected End of Charge current of the application, does it seem enough for proper charge detection?

    Best regards,

    Jérémie

  • 0 in reply to user5014632
    TI__Mastermind 34775 points

    Hello Jeremie,

    I would recommend a lower Chg Current Threshold < 100mA before scaling to detect charge currents near to full, but it will depend on what your quit current threshold is.

  • 0 in reply to Damian Lewis
    Intellectual 515 points

    Hi Damian,

    Thank you for your answer, I will divide all thresholds by the scaling factor of 4, this will lead to the following values:

    • Dsg Current Threshold : 15 (translates to 60 mA)
    • Chg Current Threshold : 20 (translates to 80 mA)
    • Quit Current : 10 (translates to 40mA)

    The lowest taper current I use is 168 mA (42 after scaling), does this sound good to you?

    Could you elaborate on the use of Res Current? The scaling yields a result of 2.5, shall I set '2' or '3' for this parameter?

    And finally, is it safe to modify these parameters on existing golden images without doing again the learning cycle? (see the use case we've discussed on )

    Best regards,

    Jérémie

  • 0 in reply to user5014632
    Intellectual 515 points

    Hi Damian,

    I ran a learning cycle with the following thresholds:

    • Taper Current: 84 (scales up to 336mA)
    • Min Taper Capacity: 6 (scales up to 24mAh, or most likely 0.024mAh)
    • Cell Taper Voltage: 150mV
    • Dsg Current Threshold: 15 (scales up to 60mA)
    • Chg Current Threshold: 20 (scales up to 80mA)
    • Quit Current: 10 (scales up to 40mA)

    However, the learning failed because FC was never set at the end of charge. This is the first time I try a C/100 taper current, and the issue seems related to this topic:

    Any update on this behavior since last year?

    Can you precise what "Res Current" is used for? This parameter seems to have disappeared on the last version of BQstudio, do I still have to scale it? How?

    And once again, is it safe to modify these parameters after a learning cycle?

    These are important information to ensure the end of charge will be correctly detected by the gauge. Thank you for your help.

    Best regards,

    Jérémie

  • 0 in reply to user5014632
    Intellectual 515 points

    Hi Damian,

    Any update on this topic? I would like to close it with every point answered.

    Best regards,

    Jérémie

  • 0 in reply to user5014632
    TI__Mastermind 34775 points

    Hi Jeremie,

    That seems fine.

  • 0 in reply to user5014632
    TI__Mastermind 34775 points

    Hello Jeremie,

    user5014632 said:
    Any update on this behavior since last year?

    No, you should try a larger taper. I would recommend running learning cycle without scaling then apply scaling after.

    user5014632 said:
    Can you precise what "Res Current" is used for? This parameter seems to have disappeared on the last version of BQstudio, do I still have to scale it? How?

    It's the minimum load current that would allow resistance (Ra) to be updated.

    user5014632 said:
    And once again, is it safe to modify these parameters after a learning cycle?

    Yes, learning is for learning resistance (Ra) and Qmax

  • 0 in reply to Damian Lewis
    Intellectual 515 points

    Hi Damian,

    Thank you for your answer.

    Best regards,

    jérémie