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Original question:

BQ40Z50-R2: Auto Ship Shutdown sometimes not working

BQ40Z50-R2: Followup on "Auto Ship Shutdown sometimes not working"

Sebastian Manz
Intellectual 470 points
Part Number: BQ40Z50-R2
Other Parts Discussed in Thread: BQSTUDIO

Hi,

finally I got my hands on batteries with which I was able to reproduce the problem. I can't answer on the original thread however, since it's locked now.

It turns out that the problem only shows up if the impedance tracking (GAUGE_EN) is disabled. If impedance tracking is disabled, some of the batteries will not enter shutdown properly (but some still might). However if impedance tracking is enabled, they all enter shutdown properly.

I tested with 15 sorted out batteries. They all did not enter shutdown before. After I activated impedance tracking 14/15 did enter shutdown after a while. (One still does not, after testing it two times. I have no idea why.) I even did the backwards test and disabled impedance tracking of three batteries again and they went back to the old behavior and did not enter shutdown anymore.

Of course I now know how to fix the problem. But why the heck does disabling impedance tracking interfere with shutdown behavior? Did I miss something in the reference doc?

Best regards,

Sebastian

  • 0
    TI__Guru** 105740 points

    Hello Sebastian,

    Let me check with the firmware team, the only thing I can think is that since the gauging is running, before we go to shutdown the gauge has to do some additional cleanup which adds time before we enter shutdown. This extra time delay allows the voltage to drop on the PACK pin for slightly longer before it is checked again when the gauge goes to shutdown. Essentially this added buffer allows the gauge to enter ship mode. But I want to confirm with the other teams first.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    TI__Guru** 105740 points

    Hello Sebastian,

    Can you do a quick test with one bad gauge and one good gauge (one with GAUGE_EN=1 and one with GAUGE_EN=0) make sure lifetime data is enabled and then set the auto ship time to 1 or 2 minutes. After you waited maybe 15 minutes if the gauge hasn't entered shutdown, click the LT_FLUSH command on the side bar in BQStudio, this forces the lifetime data in RAM to be saved in flash.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Intellectual 470 points

    Hello Wyatt,

    with auto ship time set to two minutes, both the good and the bad battery enter shutdown after less than three minutes. My previous tests were with auto ship time set to one day. I will repeat this test with auto ship time set to one day.

    What do you want me to do after reproducing the problem and clicking LT_FLUSH?

    Best regards,

    Sebastian

  • 0 in reply to Sebastian Manz
    TI__Guru** 105740 points

    Hello Sebastian,

    After doing the LT_FLUSH command export the .gg file for both. I want to look at the lifetime data for shutdowns, on the previous thread when you pulled the .gg file the lifetime data may not have been updated since we do not update the values constantly, unless you send the command.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Intellectual 470 points

    Hello Wyatt,

    I sent you the data via pm.

    Thanks,

    Sebastian

  • 0 in reply to Sebastian Manz
    TI__Guru** 105740 points

    Hello Sebastian,

    Let me check with the firmware team on this.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    TI__Guru** 105740 points

    Hello Sebastian,

    The only other main criteria from the FW teams initial feedback was if the gauge is in sleep mode, the gauge must be in sleep mode in order to go to shutdown.

    Waiting for further feedback from the FW team from your tests.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    TI__Guru** 105740 points

    Hello Sebastian,

    FW team said that the gauge enable should not affect the process of entering shutdown. Are any other settings being changed like FET_EN during the testing, or is it only the gauging that is disabled?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Intellectual 470 points

    Hello Wyatt,

    of the two tests which I sent you the data for, the only difference was the GAUGE_EN command sent to three of the six batteries.

    Best regards,

    Sebastian

  • 0 in reply to Sebastian Manz
    TI__Guru** 105740 points

    Hello Sebastian,

    Can you verify the gauge is in sleep mode by measuring the current consumption of the two gauges? There should be longer time periods between current spikes when the gauge is in sleep.

    The only other conditions that would stop from entering shutdown would be the conditions for entering sleep, since this is a requirement to enter shutdown.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Intellectual 470 points

    Hello Wyatt,

    unfortunately I'm no longer ordered to make investigations on the subject. We are able to fix the symptom of the problem by having impedance tracking activated.

    Thank you for your help.

    Best regards,

    Sebastian