bq40z60 - Learning Cycle not starting with bqStudio

Charley A.

Other Parts Discussed in Thread: EV2400, BQSTUDIO, BQ40Z60

I am attempting to initiate a Learning Cycle on a 4-cell Li-Ion pack with bqStudio 1.3.35 through an EV2400 interface. But I get an error message: "No Acknowledgement from Device."

The bq40z60 on the EVM is in unsealed mode and I am able to read/write to data flash.

I set Design Capacity, Design Voltage, and Minimum output Voltage / Voltage Resolution according to Top and Bottom Resistors.

I select "Manual Mode" for learning cycle, then set the termination voltage to 3000mV, and click "Start." Then, I connect the load (a DC fan) when prompted.

The status messages received are:

Thu May 14 15:23:35 PDT 2015: Learning cycle started...
Thu May 14 15:23:35 PDT 2015: Start task: Discharge ( TerminateVoltage = 3000 mV )

But nothing happens after that and "No Acknowledgement from Device" appears. Did I miss a step?

over 8 years ago

0 Charley A. over 8 years ago

Intellectual 430 points

I do notice that the XDSG register bit is set, but none of the Safety Status or PF register bits are set.

0 ThomasCosby over 8 years ago in reply to Charley A.

TI__Guru 73830 points

Charley,
I have not tried the Learning Cycle tool. I will try it tomorrow to determine why it is not working for you.
Tom

0 Charley A. over 8 years ago in reply to ThomasCosby

Intellectual 430 points

Thanks, Tom. Here is the register status if it is helpful.

EDIT: I updated the firmware from v0_13_build_13 to build_19. No change.

0 ThomasCosby over 8 years ago in reply to Charley A.

TI__Guru 73830 points

Charlie,
The flags show that the FETs are not enabled. You can send the FET_EN command 22 to turn them on. I tried the Learning cycle tool and had some issues using it and I am working with the tools team to fix it. You can run the optimization cycle without the tool until we can get it fixed.
Tom

0 Charley A. over 8 years ago in reply to ThomasCosby

Intellectual 430 points

Hi Thomas

I found a procedure for manually performing the learning cycle. Can you confirm that this is correct?

Discharge battery to empty
Relax for 5 hours
- At the end of this relaxation and before the charge process, make sure that IT is enabled. You can enable IT by sending the IT_ENABLE Control() Subcommand (please refer to device specific data sheet).
Charge battery to full
- We typically recommend a C/2 charge rate
Relax for 2 hours
Discharge battery to empty
- We typically recommend a C/5 rate, but the rate can be as low as C/10.
Relax for 5 hours

Source: http://www.ti.com/lsds/ti/power-management/battery-management-products-faq.page

Will the charger automatically save the impedance characteristics without a prompt/command telling it to do so?

Thanks,

Charley

0 Onyx Ahiakwo over 8 years ago in reply to Charley A.

TI__Guru* 76230 points

Yes the gauge will automatically save the resistance of the cell. Just make sure to have IT enabled as explained in point 2.
thanks
Onyx

Power management

Power management forum

bq40z60 - Learning Cycle not starting with bqStudio