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bq34z100 Qmax learning

Daniel Huhn
Prodigy 40 points
Other Parts Discussed in Thread: BQSTUDIO, BQ24170, BQ34Z100

Hello,

i have problems to calibrate the Qmax of the battery.
I use the bq34z100 with bqStudio 1.3.45 and the Charger is a bq24170.

The Battery properties are:
7Cells parallel Panasonic NCR18650B.
Capacity: 22.4Ah
Energy: 82.2Wh

At the beginning I have calibrated the offset of the board and set the Chemistry-ID to 2012.

Configuration of the FuelGauge:
Taper current: 224mA
Design Capacity: 22400 mAh
Design Energy: 8220mWh
Design Energy Scale: 10

For calibrating the battery, i was using the following steps:

1. Send an IT Enable (21) command to turn ON FETs. Send a Reset command (41) to disable Ra-table updates.
2. Discharge to empty
3. Wait until the OCVTAKEN flag turns red.
4. Send IT Enable command to set a DOD0 reference point.
5. Charge to full (FC bit set.)
6. Wait until the OCVTAKEN flag turns red. You should see VOK turn green after Qmax has learned. You should see Update Status change to a 05.
7. Discharge at a C/8 rate down to Term Voltage.
8. Wait until the OCVTAKEN flag turns red. You should see Update Status change to a 06 during the rest period.

But on step 3 the OCVTAKEN flag doesn´t go to red and the RUP_DIS, QEN flags are red and VOK is green.


I am waiting for 8 hours and there are no changes.


What is the problem?

Thanks for help,

Daniel

  • 0
    TI__Guru 73830 points

    Daniel

    You will need to verify that you have a good ChemID match to your cells and we have an online tool to help with that.

    This will be a better optimization cycle for the bq34z100. Be sure to log data through the entire process.

    • Configure the dataflash with appropriate parameters suitable for your application; configure pack's chemistry and perform calibration.
    • Activate impedance track.
    • Charge the pack to charge termination.
    • Allow the pack to rest until the OCVTIAKEN flag sets.
    • Discharge the pack at a C/10 to C/5 rate to the Termination Voltage.
    • Allow the pack to rest until the OCVTAKEN flag sets. Qmax should update and Update Status should increment to 05.
    • Fully charge the pack to charge termination.
    • Allow the pack to rest until the OCVTAKEN flag sets.
    • Discharge the pack at a C/10 to C/5 rate to the Termination Voltage.
    • Allow the pack to rest until the REST flag sets. The Ra table should update and Update Status should increment to 06.

    You can then run a couple for cycles to check the gauging performance and then move forward to creating the golden file that can be used to program additional packs.


    Tom