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  • TI Thinks Resolved

BQ34Z100-G1: Sudden Jump in Remaining Capacity

Part Number: BQ34Z100-G1

Hi

When dischaging the TrueRC jumps down and up. After one hour or so with no load SoC suddendly jumps from 51% to 83%.

I am using BQ34z100-G1 on a 10s1p pack consisting of Eneloop AA cells. The ChemID has been found to 6100 and the learning cycle has been sucessfull.

What could cause the SoC to jump like this? 

Best regards

Jostein Håvardsholm

  • Hi Jostein,

    Please zip and upload the log of the SOC jump event along with the gg.csv file for analysis. Thank you.

    Sincerely,
    Bryan Kahler
  • In reply to user3798751:

    Hi Bryan

    Thanks for checking this. I have performed two discharge cycles with different loads. The common factor seems to be a jump in SoC when the battery voltage has risen to 13.11V. The SoC jumped to from 51% to 83% and 26% to 84%.

    Best regards
    Jostein
  • In reply to user3798751:

    Hi Bryan

    Our pilot series has to be reworked and I am holding a shipment of 100 boards at the factory while trying to solve this issue. I realy hope you can assist.

    Can I easily turn BQ34z100-G1 into a "dumb" coloumb counter with a fixed FCC? This may save us some of the rework.

    Please notice that the gauge is configured to be used as a system-side. Could this be causing the SoC jump?

    I have attached the ChemID files in case you can find someting of interest.6557.config-report.zip2450.config.zip

    Best regards

    Jostein

  • In reply to user3798751:

    Hi Jostein,

    Thank you for providing the chemID files. I understand the urgency and will update this thread tomorrow (Friday).

    Sincerely,
    Bryan Kahler
  • In reply to Bryan Kahler:

    Hi Bryan

    I exchanged to ChemID 6108 and tested but the issue remained. ChemID 6108 point toward HR-43AU (4000mA) from FDK. From the datasheet HR-43AU has a voltage profile that is more similar to HR-3UTG (2000mA) used in our design. ChemID 6100 found using TI's online tool points toward panasonic HHR380. This cell has a slightly lower voltage profile under load comparred to the FDK cells.

    See attached zip files for this discharge.

    Best regards

    Jostein

    DF7 and Chem ID 6108.zip

  • In reply to user3798751:

    Hi Jostein,

    Thank you for the update. Will analyze these files as well. Could you also send me the zip archive that you submitted to the GPCCHEM tool (including log and config.txt) that resulted in suggestions for the 6108 and 6100 profiles?

    Sincerely,
    Bryan Kahler
  • In reply to Bryan Kahler:

    Hi Bryan

    I have only submitted to the GPCCHEM once and the result was 6100. To search for error I replaced 6100 with 6108, but this did not help. See attached files. I have already added these files, so please let me know if you are searching for somthing else.

    Do you have and example of a .gg file for a comparrable battery? I need an idea for a new test.

    Best regards

    Jostein

    1581.config.zip

    8463.config-report.zip

  • In reply to user3798751:

    Hi Jostein,

    After analyzing the logs, it appears the packs were not learned prior to the discharge tests. Please either run a learning cycle prior to the discharge tests or use the GPCRA tool to learn the cells prior to the discharge tests.

    To learn the packs:

    0. Configure dataflash, pack chemistry, perform calibration and export GG File (for later comparison)
    1. Enable IT
    2. Send Reset command (0x0041)
    3. Charge the pack to charge termination.
    4. Rest until the OCVTAKEN flag sets
    5. C/5 Discharge to the termination voltage
    6. Rest until the OCVTAKEN flag sets. At this point, QMax should update and the Update Status should increment to 0x05
    7. Charge the pack to charge termination
    8. Rest until OCVTAKEN flag sets
    9. C/5 Discharge to the termination voltage
    10. Rest until the OCVTAKEN flag sets. At this point, the Ra table should update and Update Status should increment to 0x06

    This is most likely the root cause of the SOC jumps.

    Sincerely,
    Bryan Kahler
  • In reply to Bryan Kahler:

    Hi Bryan

    I have already performed a good learning cycle where the Update Status was changed to 0X06 (see attached zip). After that I prepaired the pack for production by resetting the lifetime data and changed the Update status to 0x02 according to SLUA334B (reffered to in the datasheet of BQ34z100-G1). SLUA334B instructs to set Update Status to 02. I did that using Battery Management Studio, not notepad as per SLUA334B.

    See attached .gg files from the learning cycle. I will load the unmodified flash data retrived directly after the learning cycle and test again. Please let me know if you still like me to repete the entire learning cycle.

    Best regards

    Jostein

    DF7 learning cycle.zip

    Learning cycle flash DF7.zip

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