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BQ34Z100: Cannot reach FC

Kornel Straub
Prodigy 170 points
Part Number: BQ34Z100
Other Parts Discussed in Thread: GPCCHEM

Hello,

I'm trying to configure and run optimization cycle on a BQ34Z100EVM with Panasonic LC_P1220P battery pack. I've discharged the pack even below the recommended value of 10.5V (till 9.5V) and charged with 2.1A (bit above C/10) to 13.9V and waited until current has dropped to 20mA, but no FC is detected and CHG bit is still set. (The SOC do not go above 91 % and the True RC above 17.4 Ah.) The FC Set in the config is set to -1, therefore, the charge termination should be detected when the current drops below the configured taper current while the voltage is above the configured limits. (The config and the log of the end of charging are attached.)EVM_Pana_LC-P1220P_03.gg.zipCharge05End.zip

What have I missed?

Thanks,
Kornel

  • 0
    TI__Guru* 76230 points
    Hi Kornel.
    Pls attach your gg file a well. If you have not completed your learning cycle, there SOC will not be accurate. Did you identify your chem id following the instructions in our tool gpcchem? Did you check to make sure you are meeting primary charge termination conditions?

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 170 points

    Hi,

    The gg file has been attached to the original post named EVM_Pana_LC-P1220_03.gg.zip. To be sure I attach here, again.

    2816.EVM_Pana_LC-P1220P_03.gg.zip

    We have chosen this battery for the single reason because it is existing in the chemistry database. I simply downloaded that chemistry (0x0803).

    My problem is that I cannot find, which of the charge termination conditions is not met. The voltage was high enough, the current was below the taper limit and still high enough to fit the 0.25mAh/window. That's why I asked, what had I missed?

    Thanks,
    Kornel

  • 0 in reply to Kornel Straub
    TI__Guru* 76230 points

    Hi Kornel

    Sorry for the delay to this. Your files had me scratching my head for a while  until i finally figured out what your problem is.

    You are using a 1s system, yet your number of series cells is set to 6 in data flash. You need to change that to 1 and issue a reset commandfor the gauge to be able to see FC flag get set.

    thanks

    Onyx

  • 0 in reply to Onyx Ahiakwo
    Prodigy 170 points

    Hi,

    Now I'm completely confused. The pack I'm using contains a series of 6 PbA cells. Most of the config parameters of the gauge is meant for a single cell. The log I've attached was created with Battery Management Studio. Which is regardless of the cell number reports voltage for a single cell. Maybe this causes confusion.

    Or I've completely misunderstood the concept of using the gauge. Your answer suggest that I should treat the whole 6s pack as it would be a single cell. In this case not only the number of cells should be set to 1, but all cell related voltage values should be pack voltage. Also the voltage calibration should be redone to pack voltage. It also means that the chemistry 0x803 for the Panasonic LC_P1220P has been created using this single cell concept.

    Am I right or misunderstood something, again?

    For my understanding, does it mean I have to use cell number >1 if I connect the gauge to a single cell of a multicell pack and use cell number=1 if I measure the whole pack?

    Thanks,
    Kornel

    P.s: I you have chemistry for LC-P1220P you should a valid config for the gauge as well. Could you, please, send it to be able to compare with mine?

  • 0 in reply to Kornel Straub
    TI__Guru* 76230 points
    Hi Kornel,
    pls address the following:
    -are you using the EVM or your board?
    -if using the EVM did you configure the EVM hardware for multicell? Your cell voltages in the log file are supposed to reflect the total number of cells times the voltage of one cell. However, your log file is only showing one cell. Pls follow the instructions in the EVM user guide for setting the EVM up for multi-cell given you have a 6s configuration.
    Your voltage should read arond 12V for the 6s.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 170 points

    Hello Onyx,

    I'm using the EVM and it's configured for multicell. The only thing I've missed is that I have to calibrate the voltage divider to show the pack voltage instead of cell voltage. I've recalibrated it and run through a charge/discharge cycle and almost everything look OK.

    I've done the charge/discharge according to thread

    After charging (~C/10) the OCVTaken is set, after discharge (~C/7) the OCVTaken is set, again, but Update Status is still 04. (The SOC was already looking good.) Unfortunately, I cannot save the log, because the Battery Management Studio doesn't create log file when I try to save it (also no fault is displayed) even if I run the sw as administrator. Therefore, I've attached a screenshot from the final state.

    What did I do wrong? Or should I simply repeat the chg/dchg cycle for correct learning?

    Thanks,
    Kornel

  • 0 in reply to Kornel Straub
    TI__Mastermind 25955 points
    Hi Kornel,

    Please follow the steps in this post to log. Please let me know if you still have problems in creating a log:

    e2e.ti.com/.../396910

    Sincerely,
    Bryan Kahler
  • 0 in reply to Bryan Kahler
    Prodigy 170 points

    Hello Bryan,

    Thank you for your help. I've used the Watch window in the past to record log, which was OK sometimes, but sometimes refused to create file when I tried to save. Your suggestion solve my logging issue.

    Best regards,
    Kornel

  • 0 in reply to Kornel Straub
    Prodigy 170 points

    Hello Onyx,

    I've done a new charge/discharge cycle with the same settings, but Update Status is still 04 (as well as Learned Status). Please, find the logs attached.
    Could you, please, help what have I missed?

    Best regards,
    Kornel

    Charge_D07_02.zip

    Discharge_D07_02.zip

  • 0 in reply to Kornel Straub
    TI__Guru* 76230 points
    Hi Kornel,
    For the learning cycle, instead of struggling to get the device to update, i suggest using our online tool gpcRa to get the ra and qmax. I am stilll checking to see why FC is not getting set.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 170 points

    Hello Onyx,

    The FC issue is solved when I've recalibrated the voltage divider to report the pack voltage instead of the cell voltage.

    The only issue I've is the learning, which may be answered by your link: when I've done the optimisation cycle I haven't applied reset after the charging.
    Also when I've done the discharge the remaining SOC was reported 13%. Which means the Q is not changed enough (you mentioned min 90% in the other post).

    Therefore, I run a new charge/discharge cycle with slightly increased voltage range and bit lower discharge current (~C/8)...

    Thanks,
    Kornel

  • 0 in reply to Kornel Straub
    TI__Mastermind 25955 points
    Hi Kornel,

    Glad to hear the FC bit is flipping.

    Please let us know if everything is resolved with the added step in your process.

    Sincerely,
    Bryan Kahler