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bq40z50-r1 Learning cycle for a Heter cell

TcPaden
Expert 1085 points

Per your emailed suggestions (Aug 10), I programmed the 40z50 to Rev 1, changed the taper current to 150mA, and used a CC power supply for charging. ChemID was changed to 457 from 461, too.

REST took a long time to go high, but MaxError and UpdateStatus did not change. (No cell balancing activity, too.)

Log file is attached for your examination.


Thanks.

Tom

2015-08-06 HTCF32650 Learning Snip.zip

  • 0
    TI__Expert 3385 points
    Hi Tom,

    Can you please send an SREC file for us to take a look at as well? Also, the log file attached was from Aug 6, so was this recorded before the above changes were implemented?

    Best,
    Justin
  • 0 in reply to Justin Erfan
    Expert 1085 points

    Hey Justin,

    I did send the wrong log file: the correct one is attached, along with the srec.

    The dates don't align up because it took several days for the test, then the weekend hit.

    Thanks.

    Tom20150812 Learning attempt 4.zip

  • 0 in reply to TcPaden
    TI__Expert 3385 points
    Hi Tom,

    It appears that your cell voltages have not yet stabilized even after the 48 hour rest, and as a result you have not had a Qmax update. The first thing that I can suggest to do is to retest but give more than 48 hours and see if the cell voltages will stabilize.

    If you look at your voltage curve, your voltages are still dropping when the software tries to take a read for Qmax, but because they haven't stabilized, you will not update your Qmax.

    Best,
    Justin
  • 0 in reply to Justin Erfan
    Expert 1085 points
    Hi Justin,

    The discharging stops on 8/13, 14:17:12. The last data point was taken on 8/18, 8:25:01. That's over 4.75 days! I see what you mean about the curves, but giving even more time to stabilize doesn't seem right.

    I'm assuming we're talking about the 4µV/s requirement to reach a relaxed state?

    I'll try it again with an even longer stabilization time after discharge, but I don't hold much hope.

    Regards,
    Tom