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BQ40z50

SORIN CROICU
Prodigy 140 points
Other Parts Discussed in Thread: BQ40Z50, BQSTUDIO, BQ40Z50-R1

Hello,

I am using BQ40Z50 in a battery pack with 3 Li-Po cells. The project works well but I have a problem:

When the battery is not used , it goes into sleep mode and when I try to see the state of the charge by pressing the "Display button",

I get different readings: sometimes 3 LEDs level, sometimes 4 and sometimes 5. The problem is that the battery is fully charged and I confirmed this by connecting the battery to the "bqStudio".  BQStudio always shows the right values, and the LED reading comes back to normal. The problem seems to be with the sleep mode.

What registers do I set wrong or what do you think is the problem?

Thank you for your help!

  • 0
    TI__Expert 3385 points
    Hello Sorin,

    Can you please provide a srec file for the bq40z50 showing this issue? Also, is this the bq40z50 or the bq40z50-R1?

    Best,
    Justin
  • 0 in reply to Justin Erfan
    Prodigy 140 points

    Hello Justin,

    The file is attached.

    I use bq40z50.

    Thank you for your help,

    SorinOS2_3xSLPB283452H4_10202015_REV-2(-autoshipen).gg.zip

  • 0 in reply to SORIN CROICU
    TI__Expert 3385 points
    Hi Sorin,

    This is the GG file. Can you please send the srec file?

    You can obtain the file by going to the "firmware" tab in bqStudio. There enter a location to save the file, and press "Read Srec from device"

    The result will be a file with the extension ".srec"

    Best,
    Justin
  • 0 in reply to Justin Erfan
    Prodigy 140 points

    Hello Justin,

    Sorry for the confusion.

    The .srec file is attached.

    Thank you,

    Sorin

    0101_11052015.zip

  • 0 in reply to SORIN CROICU
    TI__Expert 3385 points
    Hi Sorin,

    I have noticed that this device has not gone through a learning cycle, and the resistance tables have not been updated. Can you please complete a learning cycle on the device?

    Best,
    Justin
  • 0 in reply to Justin Erfan
    Prodigy 140 points

    Hi Justin,

    Here is the new file after two complete charge/discharge cycles.

    Thank you,

    Sorin0101_11062015.zip

  • 0 in reply to SORIN CROICU
    TI__Expert 3385 points

    Hi Sorin,

    Looking at your Update Status, I see that bits 0 and 1 are not set. This means that your gauge has not completed a successful learning cycle and has not updated Qmax and the resistance tables.

    How did you do your charge/discharge cycles?

    Please complete a learning cycle and see if you are still having issues.

    Best,

    Justin

  • 0 in reply to Justin Erfan
    Prodigy 140 points

    Hi Justin,

    I fully discharged the battery (rate:2A) and immediately fully charge it (rate: 300mA).

    I did this cycle twice. Is something special that needs to be done during the learning cycle?

    Thank you,

    Sorin

  • 0 in reply to SORIN CROICU
    TI__Expert 3385 points

    Hi Sorin,

    The crucial point is that you need to allow enough time between the charge/discharge for the battery to relax enough for the VOK bit to be set. This bit will indicate that the voltage is relaxed enough to take a Qmax measurement.

    For reference on completing a successful learning cycle, please take a look at this app note.

    Best,

    Justin

  • 0 in reply to Justin Erfan
    Prodigy 140 points

    Hi Justin,

    Thank you for the info, I will let you know about the results next week.

    Best Regards,

    Sorin

  • 0 in reply to SORIN CROICU
    Prodigy 140 points

    Hi Justin,

    After a number of failed tries to complete the learning cycle(following all the instructions on the app note), I decided to upgrade the firmware to R1.

    So, I upgraded to R1, I found and loaded the exact cell chemistry in your data base, I changed the flash values to accommodate our application and I tried the learning cycle again. Now, after I finished the "charging part", the update status jumped directly to 2 (6 if you consider GaugeEn bit). The app says that the status should change to 1 and only after discharge would change to 2.

    Other than that, everything looks good so far. I also recorded the registers during the process. Can you please take a look at the package that I send and let me know if everything is OK?

    I have one more question: What is the best method to program the batteries for a small quantity production? Load the golden .srec on each battery and change the date and serial number?    

    Thank you for your help,

    SorinOS2_Battery.zip

  • 0 in reply to SORIN CROICU
    TI__Expert 3385 points
    Hi Sorin,

    I noticed in your first gg file (before the learning cycle) your resistance tables have already been updated, so this is why the update status will change to 06. This does not mean that the gauge is good to go, and you still haven't completed a successful learning cycle.

    Can you please flash the gauge with a new .srec (-R1 is fine) and load your ChemID and configurations? Then create a golden file at this point.

    Now after doing the above, retry the learning cycle capturing the same files you gave me in your previous post.

    This is what should happen:
    Discharge completely, relax for 5 hours (update status ->04), charge to full, relax for 2 hours (update status ->05), discharge to empty , relax 5 hours (update status ->06)

    Also for small quantity production, you can use the .srec to program the devices.

    Best,
    Justin
  • 0 in reply to Justin Erfan
    Prodigy 140 points

    Hi Justin,

    I followed all the steps that you advised me to do, but after relax(5hours) + charge + relax(>3hours), the status did not change to 5, stayed on 4. Can you please take a look at the attached log and let me know if I have some settings wrong or something...

    Thank you,

    Sorin6012.TI.zip