Chem or aux file set-up for decreased End Of Charge Voltage (4.1V)

Andreas S

Intellectual 515 points

Other Parts Discussed in Thread: BQ78PL114, BQWIZARD

We have a battery pack running with the BQ78PL114, new firmware (5k).

The cell voltage is limited to 4.1V.

The chemistry data is selected to ID 204 and the cell is the Sanyo 18650W.

I load the .aux file generated out of the logged data. During data logging, 4.1V has been End Of Charge Voltage.

Approx. only 84 % RSOC is displayed, if the cell is charged to 4.1V. If the cell is charged to 4.2V, 100% is displayed.

Do i need an other chemistry data file for the end voltage of 4.1V, or should the generated .aux file be enough?

Regards

Andreas

over 15 years ago

0 Jim M15252 over 15 years ago

TI__Intellectual 1940 points

The aux file does not contain voltage information. That is in the .chem file.

0 Andreas S over 15 years ago in reply to Jim M15252

Intellectual 515 points

that is as i expexted.

How can i modify or generate the chem-file 204 to the decreased voltage (4.1V)?

regards

0 Jim M15252 over 15 years ago in reply to Andreas S

TI__Intellectual 1940 points

A new .chem file is needed.

The Dallas BMS team coordinates the .chem file generation. You would need to send them a few cells (2 or 3).

0 Andreas S over 15 years ago in reply to Jim M15252

Intellectual 515 points

ok, i'll send some samples.

If i look to the bqWizard's - Load Chemistry Data entry, i find the ID 204 together with the Sanyo 18650 W. This is exactly the cell, i am using.

So this cell should be already evaluated by TI. Isn't it possible, to generate a .chem file once by TI for the highest possible voltage and make it possible, to post-define the developers choice of end of charge voltage (scaling factor of the LUT's output). The .chem file contains a lookup table which should be true also for lower voltages?

regards

Power management

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Chem or aux file set-up for decreased End Of Charge Voltage (4.1V)