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BQ27441-G1: BOOSTXL-BATPAKMKII Fuel Tank cannot detect battery actual capacity

Part Number: BQ27441-G1
Other Parts Discussed in Thread: BOOSTXL-BATPAKMKII

Dear TI Experts,

I have a BOOSTXL-BATPAKMKII Fuel Tank MKII Battery BoosterPack Plug-in Module and a Development Kit (MSP‑EXP432P401R).  I used to plug them together and ran its monitoring terminal which worked correctly for the original 1200mAh Li battery.

Today, I set up BOOSTXL-BATPAKMKII and MSP‑EXP432P401R Launchpad again to test a 40mAh battery which was suspected to be a bad battery.  The result was as following:

When I plugged in the 40mAh battery into my BOOSTXL-BATPAKMKII battery socket, MSP‑EXP432P401R`s UART terminal came up with non-sense unrecognisable characters.  This result matched with my suspect.  This 40mAh battery is bad.

Then, I repeated this test with another new 130mAh and new 2000mAh Li batteries.  The results are as following:

  • MSP‑EXP432P401R`s UART terminal came up again with correct fuel gauge interface and recognisable characters.  However, fuel gauge could not show my batteries` actual capacities, namely, 130mAh and 2000mAh.

Now my question is:

  • How do I correct the terminal so that it can show every inserted battery's actual capacity?

Yours faithfully,

Timmy Siu

  • Hi Timmy,

    Can you please confirm if a learning cycle has been preformed with this gauge and battery cell?

    If not, the instructions to complete this can be found below:

    https://www.tij.co.jp/jp/lit/pdf/slua903 

    Regards,

    Anthony Baldino

  • I see.  Thank you Anthony.

    I have never been acknowledged about that document.

    Other questions are:

    1. Do I have to define new macros in fuel tank`s demo project for each new battery type inserted into my BOOSTXL-BATPAKMKII Fuel Tank?

      /* BQ27441 Configuration */
      #define CONF_DESIGN_CAPACITY
      #define CONF_DESIGN_ENERGY
      #define CONF_TERMINATE_VOLTAGE
      #define CONF_TAPER_CURRENT
      #define CONF_TAPER_RATE
    2. and I must run a learning cycle for each battery type?

    Yours faithfully,
    Timmy Siu

  • Hi Timmy,

    Are you testing the 130 mAh and 2000 mAh batteries separately or are they used together?

    If you are using them separately:

    Yes, you will have to define new macros since these values will be different for each of the cells you use for the different learning cycles.

    The purpose of the learning cycle is for the gauge to learn the parameters of the cell attached (the Qmax and Ra table specifically), in which these parameters are used to accurately predict the performance of the cell. Once a learning cycle has been done for each of the cells, these values can be saved and the learning cycle will not have to be repeated.

    Regards,

    Anthony Baldino