This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

  • TI Thinks Resolved

BQ34110: Learn FCC Update Limit

Prodigy 225 points

Replies: 25

Views: 594

Part Number: BQ34110

Hello again,

After running multiple logging discharge cycles, I have noticed that FCC never updates itself by more than 256 mAh. In the BQ34110 TRM, it says "FCC cannot be reduced by more than FCC Learn Down or increased by more than FCC Learn Up during any single update cycle". "FCC Learn Down" and "FCC Learn Up" are bolded and italicized, which I assumed meant that they are data flash parameters that can be altered. However, there is no such parameter in BQStudio, and there is no other mention of these parameters elsewhere in the TRM. 

Is it possible to increase the FCC Learn Down/Up limit to greater than 256 mAh? Or, if the parameter has only enough space for a 1-byte number, is there a way to turn off the limit entirely? I am asking this because it is clear that our batteries have a full charge capacity that is significantly lower than the Learned Full Charge Capacity reported by the chip (after fully charging, the RC value is approximately 5 Ah, while the learned FCC is approximately 7.8 Ah). I know that Learned Full Charge Capacity is a data flash parameter that can be changed, but I would rather let the chip measure it automatically, just in case our charger isn't working properly somehow. At the same time, I don't want to have to do 6 or 7 charging and discharging cycles because the Learned FCC can only update 256 mAh at a time.

Thanks again for any advice you can give.

Colin 

  • In reply to Bryan Kahler:

    Hi Bryan,

    Thanks again for the reply. I couldn't find anything very helpful. I don't think either document really talked about choosing the Fit Max/Min SOC% config parameter much. I realize it has to do with curve fitting bounds but I still don't know how to choose them. If I missed something in the documents let me know.
    In the second document, we haven't been doing all the "things most commonly going wrong". Although I don't understand tip 6: "Voltage divider set to actual number of serial cell in the pack, but not for the voltage column that is selected". What does this mean? We used one 6-cell battery for the cycles, so I put 6 for the NumCellSeries = 6 config file. Does anything else have to be done? Also, I saw that "If EDVV bit is set to 1, EMF and EDVR0 have to be multiplied by the number of serial cells when written to data flash". Where is this EDVV bit? It is not in the GPCCEDV report they send back. Is it in the BQ's dataflash somewhere? I couldn't find any mention of it in the TRM.

    Thanks,
    Colin
  • In reply to ColinY:

    Hi Colin,

    The EDVV bit refers to if a fixed EDV is used (enable on some gauges). The values are absolute for other multicell gauges, however, this gauge is based on the single cell values.

    Sincerely,
    Bryan Kahler
  • In reply to Bryan Kahler:

    Ok well fixed EDV is not being used so that shouldn't be a problem. If the CEDV values are single cell then we should have programmed the correct values to the gauge as well. Any other ideas why the gauge isn't behaving as expected?

    We've tried everything we can think of, we've read the TRM and searched the forums, but we still can't find what's wrong with the gauge. I know that for batteries needing a ChemID, it is possible to ship the batteries to TI for characterization. I don't suppose that the same is possible for GPC Cycles?
  • In reply to ColinY:

    Hi ColinY,

    That's correct, the CEDV gauge doesn't require the creation of a chemID.

    Please send me your gpc report, gg.csv file and log of the event for review.

    Sincerely,
    Bryan Kahler
  • In reply to Bryan Kahler:

    Hi Bryan,

    I realize that the CEDV gauge doesn't need a chemID, I was wondering whether TI could characterize the battery for CEDV parameters like they characterize batteries for chemIDs. I have uploaded the gpc report, gg.csv file and event log previously (nothing's changed since then), however I could link them again:

    GPC Report - NEWGPC3-report (1).zip

    Discharge Log - 0358.Discharge GPC3.log

    gg.csv excel file: 8475.BQ34110GGCSV.xlsx

  • In reply to ColinY:

    Hi ColinY,

    Unfortunately, that is not offered, however, If you would like to tweak the parameters of the gpccedv tool further, here is the mathcad tool: www.ti.com/.../MATHCAD_CEDV_SOFTWARE

    It will require mathcad to use and comes with advanced instructions for tweaking parameters.

    Sincerely,
    Bryan Kahler
  • In reply to Bryan Kahler:

    Hi ColinY,

    Haven't heard from you in some time. The CEDV software is the other option than the webtool GPCCEDV.

    Sincerely,
    Bryan Kahler
  • In reply to Bryan Kahler:

    Hello Bryan,

    Unfortunately I am not very familiar with MathCAD. If problems persist and I have no other options then I can try looking into the CEDV software, but if there are other simpler possible solutions I would rather try those instead.

    Have you had the chance to look into the CEDV Report, log and gg.csv files? I know it would be quite hard to troubleshoot just off of those, but it's very possible that we have missed something that could be the source of our troubles.

    Thanks again for your time,
    Colin
  • In reply to ColinY:

    Hi Colin,

    After taking the 6 log files, submitting to the tool and then programming the values into the gauge, what issues are you now experiencing?

    Sincerely,
    Bryan Kahler
  • In reply to Bryan Kahler:

    Hi Colin,

    Haven't heard back from you in a while. Hopefully no news is good news and the issue is now resolved.

    If not, please let us know.

    Sincerely,
    Bryan Kahler

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.