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Original question:

BQ78350: Bq78350-R2 Learned FCC Update fault

BQ78350-DEVICE-FW: Bq78350-R2 Dod at EDV2 parameter

mehmet özel
Prodigy 120 points
Part Number: BQ78350-DEVICE-FW

Tool/software:

Hello Ti Team,

Our configuration file is attached. Battery FCC is 10000mAh and I am using ipsclae, so our real capacity is 100Ah.

I am using Fixed_EDV0. I noticed that DOD at EDV2 value decreases every cycle, so battery cannot calculate real capacity (real capacity is 96Ah, I measured using tester).

Why did battery decrease DoD in EDV2 parameter and why can't it update FCC?

cycle_battery01.gg.csv

  • 0
    Prodigy 120 points

    initial DOD at EDV2 is 14745.  this config file is after 76 cycles.

  • 0 in reply to mehmet özel
    TI__Guru 56126 points

    The config file alone doesn't have enough information why you don't get an FCC update. Please attach a register log file showing the discharge from full to EDV2 without an FCC update. Check TRM, https://www.ti.com/lit/ug/sluubd3e/sluubd3e.pdf, 9.1.6 Qualified Discharge, for the complete rule set. The rule set is about the actual discharge so in order to analyze why the gauge didn't update FCC, one has to have the current, voltage and temperature data (1 second log interval, ideally) that the gauge used to qualify the discharge (or in your case, disqualify) for an FCC update.

  • 0 in reply to Dominik Hartl11
    Prodigy 120 points

    Hi Dominik, 

    I will send the log file, but first can you check our log file that we created for CEDV parameters?
    Our battery is 15S, LiFePO4, CUV= 2850mV, COV 3500mV.

    When you review our log file, you will notice that the lowtemp_highrate file is different. Due to the cell chemistry, it starts at 4700mV because of low temperature and high current discharge. So could there be wrong CEDV parameters?

    Also, a simple guide to the CEDV document does not explain about the following parameters. We have selected typical parameters, are these values ​​ok?

    eve_pack_tbs_cedv_v3.zip

  • 0 in reply to mehmet özel
    Prodigy 120 points

    Hi ,

    You can find the log file in the attachment. This log file does not contain a full discharge log, only

    logs after 50% SOC.
    But I think it is still enough for you to review (I can also get a full discharge log if you want). for this battery, EDV_CMP is set.

    You can see that VDQ is high but EDV is not high at the end of discharge.

    I also noticed that the Pending EDV does not change during discharge.This may be because the EDV bit is not set.


    Anyway, I will send another log but this log is for another battery, I am working on two batteries and the second battery is using Fixed_EDV. 

    I'm waiting for your answer.

    Product3_dsg041124.logproduct3041124.gg.csv

  • 0 in reply to mehmet özel
    TI__Guru 56126 points

    These parameters are intended to be put around the knee of your voltage curve (with FitMaxSOC being well above the drop off of voltage and FitMinSOC being right after the drop off.

  • 0 in reply to mehmet özel
    TI__Guru 56126 points

    The Pending EDV changes in line 2300.  Please attach a full discharge log file.