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BQ34110EVM-796: BQ34110evm-796 monitor the battery charge status

darren
Expert 1840 points
Part Number: BQ34110EVM-796
Other Parts Discussed in Thread: BQSTUDIO, GPCCEDV

Hi everyone:

   now I use the bq34110EVM-796 to monitor the battery charge status by the bqstudio;the RSOC of the battery is 30% before 5 minutes and the charge current is about 200mA,the the battery design capacity is 2500MAH;the RSOC of the battery is up to 100% suddenly after 5 minutes and the full charge capacity is 2500MAH,the remaining capacity is 2500MAH;however the voltage os the battery is far less than the full charge voltage; the battery voltage and  the battery current has been calibrated and the voltage and current is correct by measurement;I don't know why the RSOC and charge  rise so fast and it seems unbelievable;

who  can tell me what reasons cause  this?

  • 0
    TI__Guru* 81035 points

    Hi Darren,

    Calibrating to get good voltage and current measurements is only the first step in setting up the gauge. Next you need to configure your gauge settings. The gauge settings are configured in data flash in the 'Data Memory' screen of bqStudio.

    If you are using a Li-Ion battery, you will find most of the defaults are close to what you need. If you are using a different chemistry (i.e. PbA, NiMH, LiFePO4), there are a large number of parameters that need to be updated. I have created a spreadsheet to help suggest the default settings attached below:

    /cfs-file/__key/communityserver-discussions-components-files/196/bq34110_5F00_dataflash_5F00_notes_5F00_rev03_5F00_20181002.xlsx

    The next step is to set up the CEDV (Compensated End-Of-Discharge) parameters. CEDV requires seven coefficients to enable accurate gas gauging. The CEDV coefficients ensure gauge accuracy over temperature and current load. The procedure to gather the required data and generate the coefficients can be found at http://www.ti.com/tool/GPCCEDV.

    To GPC tool requires six data log files of a continuous discharge (3 different temperatures and 2 different discharge rates). The logs should contain columns for time (in seconds elapsed), voltage (in mV), current (in mA where discharge current is negative), and cell temperature (in degrees C). Data files should be stored in csv format.

    A GPC Packager tool is available in bqStudio to package the log file to prepare it for upload to the GPCCEDV tool. The GPC Packager tool expects the data files to have a .log file extension, so renaming the .csv files to .log is necessary. Once the .zip file is generated by the GPD Packager, it can be uploaded to the GPCCEDV online tool. After a few minutes, the results containing the report with the recommended CEDV parameters will be sent by email.

    There are seven CEDV parameters in the report that should be programmed into the Data Memory:

    EMF (EMF)

    EDVC0 (C0)

    EDVC1 (C1)

    EDVR1 (R1)

    EDVR0 (R0)

    EDVT0 (T0)

    EDVTC (TC)

    Once you have obtained and programmed your CEDV coefficients to data flash, you will want to go through a full charge and discharge which will allow the gauge to learn the battery capacity. During the charge, ensure the gauge detects the FULL CHARGE condition (FC bit will be set in the device register). Also make sure the EDV_CMP bit (in Data Memory, CEDV Gauging Configuration) is set to '1' to enable EDV compensation.

    I hope this helps,

    Matt