• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 62 subscribers
  • Views 302 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ27750EVM-837: BQ27750

M Schneider
Prodigy 95 points
Part Number: BQ27750EVM-837
Other Parts Discussed in Thread: BQ25713, BQSTUDIO

Hello,

I try to learn on a Fuel Gauge on a fully assembled system.

charger: BQ25713, fuel gauge: BQ27750, Battery: single-cell LiFePO4 3.2V. Until the initial discharge, rest everything is fine, it behaves, how it's described in the manual. When I charge it to full, the full capacity shows more as twice the value it should be. (Nominal capacity is 10000mAh), but it's over 20000mAh when the fully charged flag appears. The time it takes multiplied the current the correct value should be about 10000.BQ27750-DUMP-21-11-11_10000.gg.csv

  • 0
    TI__Guru** 106140 points

    Hello,

    Can you provide the log data from the tests you are performing along with the schematic? It sounds like it may be a calibration related issue. Make sure you have performed a current calibration on your board.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 95 points

    Hello,

    where can I find, or how can I extract log data in the Battery Manage Studio? What do you mean by log data?
     

    Like I said, the system is fully assembled, there is an STM32 uC hanging on the I2C Bus as a master. the problem I think is the stable value of the discharge current: I'm powering a CPU module + 10" Display from the battery. But if the Battery voltage drops to much, the CPU Module and the display will shutdown. Because of this the discharge current will drop also, till the cpu module tries to start up again.
    is it possible to learn a gauge external in an Eval board with the battery attached? This way I could control the discharge current, independent from the behavior of the system. Then i would extract a golden image and apply this to the assembled system.
    Eval board with  charger: BQ25713, fuel gauge: BQ27750. Dose this make sense?

    Thanks,
    Martin Schneider

  • 0 in reply to M Schneider
    TI__Guru** 106140 points

    Hello Martin,

    Yes by logged data I am referring to the log file bqStudio will export.

    Yes you can perform the learning external to the system if it is not possible in the system. It may take a cycle or two for the gauge to adjust to the system since it will have the EVM trace resistances incorporated into the learning, this is why we prefer to do the learning in the system.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 95 points

    Hello Wyatt,

    This is the log from the last learning cycle:bqSBB.log.zip
    Would it be a god workaround to "cut" the uC from the system, and instead of the CPU Modul and Display to use an active load to make sure the discharge current is constant till the FD flag is set?

  • 0 in reply to M Schneider
    TI__Guru** 106140 points

    Hello Martin,

    The log does not look like a BQStudio log, it doesn't contain any cycle information like voltage temperature, or current.

    The start logging button should be used in BQStudio to begin the log, you should export the .gg file from before and after to compare any changes from the learning process. This is the best way to debug any issues that occur.

    Yes I would not use an actual system load for the learning cycle unless it is constant current discharge. I would use an external load if possible.

    Sincerely,

    Wyatt Keller