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BQ35100: Calculate remaining capacity with battery ER34615 (Li-SOCl2)

pham tuyen
Intellectual 520 points
Part Number: BQ35100
Other Parts Discussed in Thread: BQSTUDIO

Dear all,

I am using BQ35100 for measure capacity and warning when battery flat. I read and know need to use EOS mode. But in this mode i can't see any parametter such as percent 100-0% value as in SOH mode? Where i can get flow or algorithm to estimate capacity for this one?

thanks and regards,

Tuyen

  • 0
    TI__Mastermind 24870 points

    Hello Tuyen,

    In EOS mode, the gauge will present result in R-scale. You will need to find this inflection point on your host side.

    Section 5.3.1 explains this.

    Thanks!

  • 0 in reply to Kang Kang
    Intellectual 520 points

    Thanks Kang,

    As you said we can read R-scale to decided whether battery flat? How to know what value?

    Tuyen

  • 0 in reply to pham tuyen
    TI__Mastermind 24870 points

    Hello Tuyen,

    It is based on your first reading compared to later readings.

  • 0 in reply to Kang Kang
    Intellectual 520 points

    Dear Kang,

    I saw that ScaleR from 0-65535 then how to decide which value battery empty? Will it increase from 0-65535 when battery in used? Can we convert this value as battery percentage?

    thanks

    Tuyen

  • 0 in reply to pham tuyen
    TI__Mastermind 24870 points

    Hello Tuyen,

    That increase from 0 to 65535 is not normal. Can you send me a bqStudio log of when it does this and whether or not you sent gauge start and gauge stop in your system?

  • 0 in reply to Kang Kang
    Intellectual 520 points

    Dear Kang,

    I don't have tool so can not use bqstudio. But i am using MCU to interfcae with bq35100. This is dump data from MCU every start and stop gause every 10 second. I saw Rscalse seem not stable ,Almost time is big value such 64422  mohm and somtime 146moh..... Please give me a advice

    thanks so much

    get chem ID success, ID 12 00
    get soh: 80 %
    get scale R: 64422  mohm
    BQ35100_readByte: 05 <=====
    get status: 05
    BQ35100_readByte: 05 <=====
    get status: 05
    read data flash success
    opConfig: 82 <===============
    enable fuel gauge success
    read data flash success
    EOStrendDetection: 20
    read data flash success
    EOStrendDetectionPulseCount: 0
    read data flash success
    EOStrendDetectionPulseCountThrh: 120
    read data flash success
    getEOSDetectFlag: 00
    get current buf: d8 ff
    get current: -40mA
    get design capacity: 19000 mAh
    cmd[2]: 00 00 00 00<==========
    value: 0<===
    get used capacity: 0uAh
    designCapacityUAh: 19000000
    usedCapacityUAh: 0
    get remained capacity success: 19000000 uAh - 19000 mAh
    read data flash success

    get chem ID success, ID 12 00
    get soh: 80 %
    get scale R: 146  mohm
    BQ35100_readByte: 05 <=====
    get status: 05
    BQ35100_readByte: 05 <=====
    get status: 05
    read data flash success
    opConfig: 82 <===============
    enable fuel gauge success
    read data flash success
    EOStrendDetection: 20
    read data flash success
    EOStrendDetectionPulseCount: 0
    read data flash success
    EOStrendDetectionPulseCountThrh: 120
    read data flash success
    getEOSDetectFlag: 00
    get current buf: dc ff
    get current: -36mA
    get design capacity: 19000 mAh
    cmd[2]: 00 00 00 00<==========
    value: 0<===
    get used capacity: 0uAh
    designCapacityUAh: 19000000
    usedCapacityUAh: 0
    get remained capacity success: 19000000 uAh - 19000 mAh
    read data flash success
    disable fuel gauge success

  • 0 in reply to pham tuyen
    TI__Genius 10370 points

    Pham,

    In EOS mode the gauge will report out MeasuredZ and ScaledR. MeasuredZ is the raw impedance calculated and the scaleR is adjusted on the learning pulse to correlate to our Ra impedance table. In addition to these values SOH is also reported as a percentage 100-0. The SOH command is the exactly the same in SOH mode. 

    The value comes from a comparison of the Ra table and the scaledR.

    I do not understand what you mean by the "Battery Flat". The gauge will set the EOS flag when it identifies the impedance is growing at an increased rate near the end of life. 

    Thanks,

    Eric Vos