• State TI Thinks Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 3 answers
  • Subscribers 64 subscribers
  • Views 1240 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.

BQ40Z80: bq40z80 current scaling

Adam
Expert 1215 points
Part Number: BQ40Z80
Other Parts Discussed in Thread: BQSTUDIO

Hello,

I'd like to ask what is best solution when I have:

5S LiPol battery, 10Ah.

Then I'd like to measure current up to 60A, however in the system I can have 120A in peak

Then should I set Scale Factor for 60000/32767 or 120000/32767?

Another question is that I have 120A in peak possible then I'm exceeding 100mV at 1mOhm resistor, so should I maybe use smaller shunt resistor loke 0.5mOhm?

Regards,

Adam

  • 0
    Expert 1215 points

    Another thing:

    Is the ROSC calculated based on Voltage value and Design Voltage setting?

    I do have:

    And ROSC is shown 100% - why is that?

    Also what could be the reason to have ASOC 0%? - I am after calibration and Data Flash Configuration Settings set, lerning cycle not done.

    Adam

  • 0 in reply to Adam
    TI__Mastermind 24870 points

    Hello Adam,

    Unfortunately, there is a FW bug in scale factor for the bq40z80. We are releasing a maintenance release eventually.

    For now, I would calibrate 50 amps as 25 amps using bqStudio and just scale all the capacities such as design capacity by a factor of 2.

  • 0 in reply to Kang Kang
    Expert 1215 points

    Hello,

    it seems current calibration with scale factor seems work with me.

    Could you be more specific? What is this bug about?

    Could you maybe help with the seond issue as well? (Is the ROSC calculated based on Voltage value and Design Voltage setting?)

    Thank you, 

    Adam

  • 0 in reply to Adam
    TI__Mastermind 24870 points

    Hello Adam,

    If you look at the Cell Currents vs the AvgCurrent, you will see we don't apply the scaling to cell currents.

    RSOC is computed based on RemCap/FCC which are simulations. Please refer to theory of impedance track applications note.

  • 0 in reply to Kang Kang
    Expert 1215 points

    Thank you,

    one question to Learing Cycle:

    At point 4.2.3 of SLUA848 (begin of chaging) the VOK does not set automatically, tried several times. What could be a problem?

    I have GAUGE_EN set and everything according to instruction also set.

    Regards,

    Adam

  • 0 in reply to Adam
    TI__Mastermind 24870 points

    Hello Adam,

    For VOK to set, you will want to have the packs in relax mode for several hours. That will make sure the gauge will take an OCV.

    Thanks!