BQ34Z100-G1: Changing Battery Chemistry

Hi Meet,

To quickly begin communicating with the gauge, please follow this quickstart guide: www.ti.com/.../sluubv2

This will get you up and running with 4 V. Set FLASH UPDATE OK VOLTAGE = 1000 mV

After communication has been established, if the cell is less than 5 V, leave the device in less than 5 V mode.

If the battery is greater than 5 V, change VOLTSEL = 1 and then power down the device. Please set the external voltage divider on the board accordingly, as described in: www.ti.com/.../sluu904

With the external divider (16 V, 32 V or 48 V mode) jumper set( and >5 V jumpers set, please power up the device at your higher voltage.

Click on the 'data memory' button on the ribbon in bqStudio to open up the Data memory pane. If the voltage divider is set to 16 V, set voltage divider to 19182. If the voltage divider on the EVM is set to 32 V, set voltage divider to 37364. If the voltage divider on the EVM is set to 48 V, set voltage divider to 55545.

Click on the 'calibrate' button on the ribbon in bqStudio to open up the calibration pane.

Select the checkboxes for 'calibrate cc offset' and 'calibrate board offset' and click the calibrate button.

Once this calibration has finished, please deselect all check boxes and calibrate voltage, as described in this video: training.ti.com/bq34z100-g1-voltage-calibration

Once voltage calibration is finished, perform current calibration, as described in this video: training.ti.com/bq34z100-g1-current-calibration

Next, we will perform a chemID match of your battery.

Replace the power supply with your battery. Hook up your charger. Allow the cell to reach equilibrium at room temp.

Using bqStudio, click on the registers button in the ribbon. Click on Start log to begin logging. Fully charge the cell and then allow the cell to relax. Once relaxed, discharge the cell at a C/20 rate until fully discharged, and allow the cell to fully relax. Now, end the log. For specific instructions with respect to Lead Acid, please refer to section 3.4 of the GPCCHEM guide, found here: www.ti.com/.../slva725

Please create a zip file with the log and config as described in the GPCCHEM guide, linked above. With the archive created, please submit it to the GPCCHEM tool found here: http://www.ti.com/tool/gpcchem

To watch a video guide with respect to single cell devices and lithium-ion chemistry (very similar), performing this above described process,
click on this link: training.ti.com/chemistry-id-matching-online-gpc-tool . Please note: The rest times and charge/discharge rates recommended in the video for litihium ion are not the same for lead acid. Please refer to the GPCCHEM guide instructions in Section 3.4 for the lead acid instructions (linked above).

The GPCCHEM tool will return a recommend chemID for use with your device.

In bqStudio, click on 'Chemistry' in the ribbon. Scroll down and select your chemID. Then, to program the chemID to the device, select the 'Program Selected Chemistry' button.

After successful programming of the chemID, please modify your device parameters for Lead acid gauging with your battery, as described in the device datasheet: www.ti.com/.../bq34z100-g1

The default values for the device are set for lithium ion. Make sure to set the voltage values 'per cell'. The SERIES value should be set to the number of cells in series in your pack. For example, a 12 V lead acid battery has 6 cells in series. The datasheet linked above describes changes that need to be made in detail. Please pay careful attention with respect to section 8.

Once configured, please run a learning cycle that includes two complete discharges. Ensure that update status = 0x06. Please do not manually override the update status to 0x06, as the pack will not be learned.

The basic process of a learning cycle is described in this document: www.ti.com/.../slua777.pdf

In short, for lead acid, the learning cycle should look like this:

0. Configure dataflash, pack chemistry, perform calibration and export GG File (for later comparison)
1. Enable IT
2. Send Reset command (0x0041)
3. Charge the pack to charge termination.
4. Rest until the OCVTAKEN flag sets
5. C/5 Discharge to the termination voltage
6. Rest until the OCVTAKEN flag sets. At this point, QMax should update and the Update Status should increment to 0x05
7. Charge the pack to charge termination
8. Rest until OCVTAKEN flag sets
9. C/5 Discharge to the termination voltage
10. Rest until the OCVTAKEN flag sets. At this point, the Ra table should update and Update Status should increment to 0x06

At this point, the gauge should be fully learned and ready to measure SOC.

If you have any questions, please let me know.

Sincerely,
Bryan Kahler