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BQ27426EVM-738: BQStudio - configuration and golden image

Intellectual 810 points

Replies: 5

Views: 1055

Part Number: BQ27426EVM-738

Hello,

I'm trying to create the golden image for a 10000mAh 3.85V (max charge 4.4V) battery. From my understanding, I have to:

  1. Connect the BQ27426EVM to the EV2400
  2. Open BQStudio
  3. Set the Chemistry ID to 3142 (for a 4.4V max charge voltage)
  4. Set the design capacity to 10000mAh, design energy to 38500, termination voltage to my system's voltage, and taper rate based on my taper current
  5. Perform the golden image learning cycle

However, I'm having trouble with step 4: when I enter the Data Memory menu, Chemistry menu, State submenu, BQStudio complains that the value 10000 is out of range for the design capacity. Is this the correct way of configuring the device?

Thanks

5 Replies

  • Hi Nicolas,

    That means the design capacity you are trying to use is larger than what that gauge can support. 

    You will have to try using the scaling method described in section 3 of the app note below otherwise your next best bet will be to use any of our flash based gauge like the bq27520 which can support greater than 10000mAh batteries:

    thanks

    Onyx

  • In reply to Onyx Ahiakwo:

    Excuse me, but the TI site states that the BQ27426 handles batteries of up to 14000mAh. Is the site wrong?
  • In reply to Nicolas Venturo:

    unfortunately, the limit implemented in the tool (bqstudio) doesn't correspond with what we have online. Let me refer your case to the product specialist responsible for this device so he can check with the firmware engineers what the max is that the gauge can support without the math running into overflow issues. If indeed the gauge can support greater than 10000mAh without scaling, then the limit in the tool would have to be lifted to reflect what is on the website.. If it can't then, then what we have on our website would have to be corrected. We will get back to you.

    thanks
    Onyx
  • In reply to Onyx Ahiakwo:

    Nicolas.

    replace 0426_2_02-bq27426G1.bqz file with the  the attached file in the config folder of bqstudio. This will open allow program >  10000mAh in the gauge.

    0426_2_02-bq27426G1-DC.bqz

    thanks

    Onyx

  • In reply to Onyx Ahiakwo:

    Hello Onyx,

    That file indeed allowed me to set a capacity of 10180mAh, but now I cannot set the proper design energy (39193mWh).

    Thanks

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