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Original question:

BQ34Z110: Help for configure the Design capacity ,Design energy Scale and Qmax cell

BQ34Z100: About scaling current and energy.

Hai Nguyen5
Intellectual 450 points
Part Number: BQ34Z100

Hello,

I'm working on 14S8P battery, single cell properties are: 3.6V nominal voltage, 5000mAh capacity.

So, Design capacity and design energy of the battery will be:

- Design Capacity : 5000 x 8 = 40000 mAh. This value exceeds the maximum Design capacity (29.4Ah) that bq34z100 supported.

- Design Energy : 3.6 x 14 x 40000 =  2016000 mWh  > 32767.

I known that, we can scale the current and energy. For the energy I known we can use the Design Energy Scale register but I didn't see any register for scaling current.

Hope my question is clear.

Thank you in advance. 

  • 0
    TI__Genius 12215 points

    Setting the Design Energy Scale only determines that the energy related parameters has to be entered to the gauge according to the scaled unit, the affected parameters are: Design Energy, Reserve Energy(mW/cW), Avg Power Last Run, User Rate(mW/cW).

    if you want to scale the current with a desired scale, the scale must between 1 to 10, you need to set the SCALED bit in pack configuration. then you need to calibrate the current according to the expected scale factor, if you use a scale of 5, they you can calibrate the gauge with a 5A actual current then calibrate it to 1A.

    It is host's responsibility to interpret the read values.

  • 0 in reply to Steven Yao
    Intellectual 450 points

    Hello,

    Now I'm using 14S6P battery pack, the voltage of the pack when fully charged is 57.75V, the capacity of one cell is 4800mAh.

    - I scaled the current of 6: used 6A actual current then calibrate it to 1A.

    I set:

    - Voltage divider: 57750 mV.

    - Number of serial cell: 14. Then I calibrated the voltage to (actual voltage/14). For example, applied voltage to the pack is 57750 mV, then the calibrated one will be 57750/14 = 4125 mV.

    - Design capacity: 4800 mAh.

    - Design energy: 4.125V x 4800mAh =  19800 mWh.

    Did I set the parameters correctly?

    Thank you.