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BQ40Z50-R2: BQ40Z50-R2 RSOC constantly at 100% even with fully discharged batteries

Part Number: BQ40Z50-R2
Other Parts Discussed in Thread: GPCRA0, BQ40Z50

I was able to clear the CUV and CUVC alarms by reinstalling the firmware, CHEMID, and gg file I got back from the GPCRA0 tool. However, I now have a different issue, the charge cycle is terminated because an OC alarm trigger. I assume this is because my RSOC indication is constantly at 100%, even with a fully discharged battery. I have no idea why this is happening. I followed the instructions on your "BQ40Z50 Setup and Going to Production" video and I believe I have all my application setting correct. I have attached a copy of the gg file I got back from the GPCRA0 tool and a short log that shows hoe the charging cycle gets terminated only 3 minutes after it starts; this is with a fully discharged battery.

Thank you,

Jose Salazar8371.gg_out.csvCharge Test 2-26 2000 hrs.log.csv

  • Hi Jose,

    Let me check your files and see if there is something wrong with your configurations.


  • Hi Andy,have you had a chance to look at the log and gg files I uploaded? For what I understand, RSOC=RM/FCC but looking at the registers on my setup both RM and FCC are at 0 and I don't understand why.

    Hope to hear back from you soon.

    Thank you,


  • Hi Andy, I also forgot to ask why the gg file I got back from the GPCRA0 tool indicates that our battery has a QMAX of 12000 mAh and supposedly our battery is rated at 10000 mAh. I would expect +/- 5% variation but not 20%.

    Thank you,


  • Hi Jose,

    I took a look at your gg file. 

    I see you set the Cell Count to 2 cells. The Design Voltage is set to 8400mV, which seems a bit high to me.  

    Most Li-ion cells have an average voltage of 3.6 V to 3.8 V and may be specified on the cell datasheet or label. Design Voltage = (number of series cells) x average cell voltage.

    Also, the Term Voltage is set to 9000mV, which doesn't make sense to me. 


  • Hi Andy, thank you for your reply. I'm starting the whole process for CHEMID from scratch as you suggested and I'm having trouble getting the battery to charge because I assume the OC alarm is getting triggered. This is an issue that I've had from the start, the only way I was able to generate a log for a complete charge and discharge cycles was to bypass the FETs.

    The process I followed is: reloaded firmware for R2 V2.08, followed TI's instructions for preparing gauge for CHEMID log, enabled GAUGE and charging current starts at 2000 mA. However, charging stops a few minutes later with an OC alarm. Looking at the registers, I can see that RSOC is at 100% (with a fully discharged battery), Remaining Capacity at 0 and Full Charge Capacity at 0. I don't quite understand why these values are at 100, 0 and 0. I'm assuming that this is using some of the default values on the gauge, I did change the settings recommended for the CHEMID log as follows:

    DA Configuration - 2 cell, non-removable pack, sleep disabled.

    FET Options - charge FET=1, pre-charge FET=0

    Temperature Enable - Int TS, TS1 and TS2 enabled

    Temperature Mode Int TS = 1, TS1 and TS2 = 0

    CUV threshold = 2650 mV (cell data sheet calls for 2750 mV)

    COV threshold = 4350 mV (cell data sheet calls for 4250 mV)

    Precharge Current = 100 mA

    Precharge Start Voltage = 2750 mV

    Valid Update voltage = 3000 mV

    Charger present threshold = 3000 mV

    Design Capacity = 10000 mAh (according to cell data sheet), 8400 cWh, 8400 mV

    Terminate Discharge (TD) = 3000 mV

    Terminate Charge (TC) = 4200 mV

    I have attached a short gg file with the test results and a log. Also attached is the data sheet for the cell we are using.

    Thank you,

    JoseADDC_Bat_Log 3-2-2020.log.csvADDC_Bat_Test SPECS.pdf

  • Hi, Jose

        I found your terminate voltage is still set to 9000mV, I think this could cause 0 capacity and FCC

    "Gas Gauging","IT Cfg","Term Voltage","9000","mV"

  • Should this be 6000 mV for a 2S battery?

    Thank you,


  • Hello Jose,

    It should be based on your application and system empty voltage. Typically, 6 volts is normal for a 2S pack.

    Make sure you are reading the TRM and EVM user's guide on configuration. That may solve some of the issues you are seeing.

  • Hi Andy, I finally got things going with the CHEMID test, the issue was that I was enabling the IT gauge during this process and I guess I was not supposed to do that, none of the training documents and videos mention this. I'm now trying to get the learning process done and everything seems to go as planned, the Update Status did change from 00 to 04, 05 ,06 and 0e; however, when I upload the files to the GPC tool I keep getting a computational error and the message is as follows:

    Error: Computation was not successful, but the specific reason was not identified.
           Please check that all files are prepared according to the documentation.
           The support personnel have been informed

    I don't know if the error is with the log file, the gg file or the config file. The config file is very simple and I think I got it right but I'm not sue about the other two. Can you please help.

    I have attached the zip file I submitted to the GPC tool.

    Thank you,

  • Hi, Jose

        By deleting for data for first discharge stage, I got success, please find the attached file for your