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BQ78350: Bq78350-R2 Learned FCC Update fault

Part Number: BQ78350
Other Parts Discussed in Thread: BQSTUDIO

Tool/software:

Hello, 

I have problem about learned full charge capacity at BQ78350-R2. The update was not made after the qualified discharge. 

I have attached my gauge config file. Please review again. I want to know where I made a mistake.

Note: IPSCALE is set to 10E1

0x1 = Noted reported current and capacities are scaled by 10E1.

Thanks for help, 

DV_050724.gg.csv

  • Hello,

    We are looking into this. We will get back to you next week.

    Regards,

    Nick Richards

  • Hi Nick, 

    Thanks for your help, i am waiting for your  reply. 

    Regards, 

    Mehmet

  • Please also attach the register log file from a full charge to a full discharge. It's not possible to determine the cause with the configuration alone. We also need to see what happens during discharge and if the battery was charged high enough.

    The gauge applies several rules for FCC updates. See TRM https://www.ti.com/lit/ug/sluubd3e/sluubd3e.pdf, 9.1.6 Qualified Discharge.

  • Hi Dominik,

    I made a mistake and clicked the This solved my problem button. I am sory.

    I will make a recording tomorrow and share it with you. Did you specifically request a log or all of them log?

    I can also say that quality discharge occurs during the charge and discharge cycle, I am sure. but I think my configuration is not correct. Maybe there are incorrectly set parameters.

    Anyway, I will share it with you tomorrow.

    Dear Nick,

    I would also be very grateful if you could review our config file.

  • I need a log file (created by bqStudio, Register Log) that starts with a full charge and stops when voltage hits EDV0.

  • Hello Dominik, 

    logsforSOH.log

    This is our charge and discharge log file. I hope this log file is the log file you want to see.

    Thanks for your help. 

    Regards,

    Mehmet

  • Hello. The log file shows that VDQ = 1 all through the discharge while bit 14 (EDV2) in Gauging Status is never set. This implies that the discharge qualifies for FCC update but the cell voltage never dropped below EDV2. You use EDV compensation so we do not know exactly what EDV2 the gauge calculated. Please provide the input and the output for GPC CEDV.

    If possible, please test this again with compensation disabled (set CEDV Gauging Configuration to 0x0002). The gauge will then use your EDV2 setting of 3144mV. Your log file shows that cell voltage drops below this voltage so the gauge should update FCC if EDV2 is fixed. If this is the case then the problem is with your CEDV coefficients that you got from GPC CEDV. 

  • Hi Dominik, 

    Our log file is attached, we set the CEDV gauging conf to 0x0002. We noticed that the FCC value decreased after the discharge cycle. You are right, our problem is with EDV compensation.

    What do you suggest me now? Will there be any problems if I don't set EDV compensation (EDV_CMP)?

    Thanks, 

    MehmetSOHlog2.log

  • If you set EDV_CMP, you will have to obtain the correct CEDV parameters from GPC CEDV.

    If you don't set EDV_CMP (e.g. you don't have the correct CEDV parameters and don't have a way to generate the required log files), the gauge will not compensate EDV for a change in load or temperature, therefore FCC will update at a fixed EDV2 which may not be the correct voltage for BatLow% because this voltage shifts based on load or temperature. The end effect will be less accurate gauging.

  • Hello Dominik, 

    Thanks for your help. 

    Regards,

    Mehmet