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BQ27Z561: RemainingCapacity and FullChargeCapacity keep return zero readings

chad pham
Prodigy 145 points
Part Number: BQ27Z561
Other Parts Discussed in Thread: TEST2, BQSTUDIO, , EV2400, GPCCHEM

Tool/software:

test2_check_version_and_comments.gm.zip

I have done created the golden image using bqStudio IDE and EVM board.  I am successfully program the golden image in my board.

I am able to check for my board's chemID, and mimic all the communication between to bqStudio and EVM board, and replicate the communication steps using my MCU and my custom board's BQ27Z561, but when I tried to read out the RemainingCapacity and  FullChargeCapacity keep return zero readings and SOC result always return 100.  

I check the Control Command (0x00) and I saw the return 0x0204.  Regardless if I tried to write to 0x00  = 0x0001, result read back is 0xFFA5.  When I wrote 0x00 = 0x0002, the return is 0x0204.  

I got lost and don't know where to look next to enable the gauge to return the SOC.  Please help .

  • 0
    TI__Mastermind 27405 points

    Hello,

    This question has been assigned and will be reviewed when possible.

    Thank you,
    Alan

  • 0 in reply to Alan Frias
    TI__Mastermind 25021 points

    Hello, 

    Have you successfully completed the learning cycle? How was your chemID matched? 

    Regards, 

    Jonny. 

  • 0 in reply to Jonny
    Prodigy 145 points

    Hi Jonny,

    Thank you for your reply.  You are helping me on the other thread as well so I believe you are somewhat aware of going on.

    Good question.  I didn't perform the learning cycle.  I am assuming if I program my BQ27Z561 on my custom board, follow the golden image file from EVM board, and confirm the ChemID set the same as EVM board.  I am good to go.

    Can you please let me know if I need to perform any other steps?

  • 0 in reply to Jonny
    Prodigy 145 points

    Hi Jonny,

    Can you please elaborate the questions?

    If I use the BQ27Z561-EVM011 and bqStudio, and I saw the levels of the  RemainingCapacity and  FullChargeCapacity seems like correct.  I export the Golden Image from my eval board and program the image to another BQ27Z561 on my own board, and from your question, may I ask the next steps for me in order to read out the  RemainingCapacity and  FullChargeCapacity correctly like the EVM, I need:

    1. Successfully completed the learning cycle

    2. Download the ChemID

    to my BQ27Z561 on my board?

  • 0 in reply to chad pham
    TI__Mastermind 25021 points

    Hello, 

    I recommend reviewing the BQ27Z561 EVM user's guide, even if you are not using the EVM as this goes over the steps to set up the gauge. 

    Additionally, I recommend reading the Achieving the Successful Learning Cycle Document. 

    Regards, 

    Jonny. 

  • 0 in reply to Jonny
    Prodigy 145 points

    0336.10Ah_Capture-report.zip

    Hi Jonny,

    I think we misunderstood at some point.  At least I don't understand  your recommendation from going back and read the settings up the gauge.

    These were the steps I have done:

    1. Using bqStudio, with EV2400, and BQ27Z561 to perform the data capture with my battery, and submit to TI to get the ChemID.

    2. Got back the GPC report, attached here, result to from TI that recommend to use the ChemID 0x3241.

    3. Using bqStudio, with EV2400, to program ChemID 0x3241 to the BQ27Z561-EVM.

    3. Using bqStudio to export gm.fs from BQ27Z561-EVM.

    4. Flashed the exported gm.fs to my own BQ27Z561.

    5. Trying to querying  RemainingCapacity and  FullChargeCapacity and always got back Zero.

    Can you please help by reply with answer to indicate with all the steps I did above is right or wrong and what recommend I do it differently?

    I am so sorry to ask too many question, but I went thru multiple document and old programming guides from TI, but I actually couldn't get to the bottom of how to implement and use the gas gauge.

  • 0 in reply to chad pham
    TI__Mastermind 25021 points

    Hello, 

    Lets start with the chemID selection process. From the report received from the GPCCHEM tool, your discharge rate that you used to collect the data for the GPCCHEM tool was too high. This caused the report to not provide accurate chemID matches. 

    Please rerun the GPCCHEM data collection, making sure to follow precisely the steps outlined in the GPCCHEM User's Guide. I can tell you the issue this time is that you discharged at about a C/1.5 rate which is too fast. The discharge rate should be about C/10. 

    Regards, 

    Jonny. 

  • 0 in reply to Jonny
    Prodigy 145 points

    Hi Jonny,

    Thank you for your helps.  I will go back and perform GPCCHEM data collection again.

    I did had a post at another thread question about this error, and i got the respond said that even though the error is high but it is more likely the suggested chemID suggested will work with BQ27Z561, and due to I don't need an exact read out, I really just want to prove the BQ27Z561 is working.

    I used bqStudio and selected 0x3241 to my BQ27Z561-EVM board and it is showing the battery level correctly.

    Let put the chemID assign, I just couldn't figure out why the RMC and FCC return zero.  I could still communicate and confirm the chemkID from my BQ27Z561

  • 0 in reply to chad pham
    TI__Mastermind 25021 points

    Once you obtain the chemID please reperform the learning cycle. Once you successfully complete the learning cycle is when you should refer to the gauging accuracy. 

    Regards, 

    Jonny.