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Original question:

BQ40Z50-R1: Learning cycle

BQ40Z50-R1: Learning cycle

vishwaradhya G
Intellectual 495 points
Part Number: BQ40Z50-R1

HELLO TI

I was performing a learning cycle of bq40z50-r1 i was completed 3 steps(charge-discharge-relax-charge)everything is fine during relax time reset bit is set and vok clear,but update status is only 4 not changed to 5 what is reason behind please suggest me,And in the data memory i just enabling the update status is it required to enable update 1 and update 0 in block. i will attach a screenshot for the reference.

  • 0
    TI__Genius 12215 points

    Hi, Vish

       If the steps list of "(charge-discharge-relax-charge)" is exactly what you have done at present, then you have to a more discharge to get impedance updated, because the first discharge cycle only updates the Qmax, the second discharge cycle would update Impedance base on a correct Qmax value.

       Looks like nothing wrong with your learning cycle, just continue to discharge please.

  • 0 in reply to Steven Yao
    Intellectual 495 points

    Okay i have to discharged the battery to full after words whats the learning cycle steps again the cycles repeat until i got a update impedance is enabled.

    And my question is in the data memory any settings i do it for update status please suggest me.

  • 0 in reply to vishwaradhya G
    TI__Genius 12215 points

    Hi, Vish

        Sorry, I missed one thing, that is your update status is 4, not 6 which indicates even Qmax has not been updated. I found in the data memory you posted above, the QMAX Pack or Qmax Cell might be set incorrectly, I noticed your battery configuration is 2S, if your batteries are connected with n for parallel, which means 2sxp battery configuration, then initial qmax value for Pack and Cell should be n x single cell design capacity

  • 0 in reply to Steven Yao
    Intellectual 495 points

    Thank you Steven for your quick response,

    You mean to say Qmax pack is all so a single cell design capacity(4400 MAh) i will correct it and repeat the cycle again.

  • 0 in reply to vishwaradhya G
    Intellectual 495 points

    [quote user="vishwaradhya G"]

    Hello Steven,

    I was attached a screenshot of my learning cycle steps everything is looking fyn,but the Qmax value is not taking for learning cycle and also OCVFR bit is not set in relaxing mode,am using 2s-2p battery configuration design capacity mentioned in the cell data sheet is 2500 Mah, So i calculated Qmax (2500*nor of parallel cell(2))=5000 but still Qmax is not taken for further process.Please let me give the solution.

  • 0 in reply to vishwaradhya G
    TI__Genius 12215 points

    Hi, Vish

        Since you are using a 2s2p configuration, then you can set QMax Cell 3 and QMax Cell 4 to 0.

        OCVFR bit indicates whether the battery is in Flat Voltage region, the present voltage is 3.5v or so, it is no problem for this bit being cleared.

        The thing I am not clear is that for a battery in the learning cycle, it should relax at this voltage, it should relax either when fully charged or fully discharged.

        When fully charged, you should see FC bit set in the first place at valid charge termination and then VOK clear after a valid DOD update happened. Then the discharge can be started until the voltage drops to 3v or a little bit lower to make sure Qmax updated at minimum error or the impedances at all grids are updated in different discharge cycles.

        Please refer to the document via the link of http://www.ti.com/lit/an/slua903/slua903.pdf for details