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GPCCHEM: No required Chemistry ID in the GPC_report [v2]

Part Number: GPCCHEM

Continue of this post - https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1023842/gpcchem-no-required-chemistry-id-in-the-gpc_report

I make 2 more tests with only one bare cell (1s1p) as was suggested and still unsuccessful. There's no required CHEM ID in report and all other variants have DOD error > 6%.

To prove my testing setup I made other tests using other battery cells and result are good - right CHEM ID in report with satisfactory DOD error.

How can I debug what's going wrong? Is there any mechanism to check differences between my results and expected on Gauging Parameter Calculator side?

Help me, please. I would not like to send one more time cells for characterization since it takes a long time.

  • Hello Alexey,

    Can you share your new logs and report using only the single bare cell? If there's no match then the only options are to use a different cell which has been characterized by TI, or to submit the cell for characterization which can take some time.

    Sincerely,

    Wyatt Keller

  • Yes, of course. Here archive which was sent to Gauging Parameter Calculator and report from it.

    I supposed to see 0496 Chemistry ID in report (HTCFR26650 3200mAh LiFePO4).

    goldencell-htcfr26650.zipgoldencell-htcfr26650-report.zip

  • Hello Alexey,

    The report states

    Best chemical ID : 487    Best chemical ID max. deviation, % : 7.98

    and later

    Max. deviations for best ID is within recommended range. Chosen best chemical ID is suitable for programming the gauge.

    Due to manufacturing tolerances, sometimes the best match may be with a different cell. That is normal. You should use the ID with closest match.

  • Hello Shirish!

    But there's no expected CHEM ID in the report and it's strange since cells have passed the characterization procedure.

    The last Chem ID in list have DOD error 14.9%, I don't think that manufacturing tolerances can be so big!

    You should use the ID with closest match.

    I need to enable cell balancing and it was recommended to me to use chemistry with error < 3%.

  • Hello Alexey,

    It is weird that the characterized cell is not matching up. Series resistances and protectors can cause differences but those are not in play here.

    The general recommendation is to use the closest match. You can try 2 methods

    1. Use the original chem ID based on cell model

    2. Use chemID 487

    You would then choose the one that gives the best accuracy after learning cycle.

    If you have been want <3%, then there is no match and there is no option other than sending in the cell for characterization. If this cell actually has a manufacturing tolerance that large, then you will be back to square one. Note that TI requires multiple cells for characterization.

    The other option is to get logs from other cells of the same type and see if the results are the same or not.