Power management

Power management forum

State Resolved
Locked Locked
Replies 26 replies
Answers 7 answers
Subscribers 64 subscribers
Views 2820 views
Users 0 members are here

Support feedback

Options

Options

Similar topics

BQ27742-G1: feul gauge battery learning cycle process

mike zhang

Intellectual 925 points

Part Number: BQ27742-G1
Other Parts Discussed in Thread: BQ27742EVM, BQSTUDIO

Hi there,

We plan to use bqstudio, bq27742evm and bq25898devm to do the learning cycle. I have read the Learning cycle procedure and the Achieving the successful learning cycle documents, and I think I got the procedure. I have some questions to ask before starting the cycle:

I know the parameter chem ID needs to be updated to match the battery under test before the cycle started. What else have to be updated in order to achieve the successful learning cycle before start the cycle?
How to send IT enable command or Reset command in bqStudio 1.3.54.1? Do I just click the IT_ENABLE or RESET button in the Commands panel on the right side of the screen window?
The procedure asks to log Data memory and Data flash during the cycle for analyse. I think I know how to set log for data memory (go Window>Preferences>data memory, enter the interval and file name), but don't know where to set the data flash log. Can you point me out where to go for the flash log?

Thanks!

Mike

over 6 years ago

0 Onyx Ahiakwo over 6 years ago

TI__Guru* 76230 points

1. Pls reference this app note on other parameters to set.
www.ti.com/.../slua777
2. yes the command panel suffices. You can also use the advanced comm window.
3. the register window has the "start log" button for log files at the top right hand corner while the data memory has the auto export button.
thanks
Onyx

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

Thanks Onyx!

BTW, is the registers log file so called Data Flash log file?

for the chem ID, I have done the several GPC tests for one battery and got different IDs for the battery, for instance, 0285 triple, 2076 once and 0281 twice. so not sure which one should use. any suggestion?

Thanks!

Mike

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

Hi Mike,
The data flash file log file is not the register log file. You can autoexport the data flash as gg files intermitently ( you can set how frequent you export). Also, you log the register from the register window.

Any one of the chem ids returned by the tool that has less than 3% DOD error would work.
thanks
Onyx

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

Thanks!

0 mike zhang over 6 years ago in reply to mike zhang

Intellectual 925 points

Hi Onyx,

I'm doing the learning cycle and following all of your guidelines. everything seems ok except the FC bit still remains clear (low) even though it passed the charge to full step. Right now it is in the relax for 2hrs step and I have OCVTAKEN set, RUP_DIS cleared, VOK cleared (QEN set all the time) and FC always low (clear). Will it affect the learning cycle result if FC remains low all the time? Should I stop the learning cycle or keep it going?

I use C/2 charge rate and charge voltage limit of 4.228V on charger (bq25898DEVM).

Thanks!

Mike

0 mike zhang over 6 years ago in reply to mike zhang

Intellectual 925 points

oh forgot mentioning updates status still remains 04 as it relaxed more than 3hrs. based on the procedure, it should be 01 or 05, right? is it due to FC bit low?

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

That is very likely. FC (fully charge) is an important condition for the gauge to learn qmax. Pls review your charge termination condition and make appropriate adjustments to your taper current, taper voltage and charging voltage so the gauge see full charge and sets the FC flag. Make sure to charge to 4.2 and discharge to 3V if that is what your cells are rated for.

thanks
Onyx

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

Thanks Onyx!

so I should stop it, right? logs are attached for review. the charger's termination current only can be set as low as 64mA. so I set gauge's charge termination tape current to 75mA (it was set 85mA, but FC still was low). I am sure the battery is fully charged up to 4.2V.

thanks,

Mike

LCRegGGLog_s4_e2e.zip

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

www.ti.com/.../slua777

Hi Mike,
I recommend setting taper to around 100mA. make sure your chg and dsg currents are less than taper and quit should be the smallest of them all. c/20 or less. the attached app note above is more elaborate on the conditions.

I wouldnt be able to review your attachement today because it is late here but if you review that document it can help you figure out what you are missing. But the FC flag getting set is an absolute requirement. Can you attach your gg file.?

thanks
Onyx

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

gg file was attached in previous post above and have followed the slua777 guidelines... tape current 85mA or 75mA (gauge side) > 64mA (charger side). it should work... mike

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

Mike,
Your Jeita charging voltages bw 10-45 deg C is 4350mV. Your taper voltage is set to 100. So except your battery reaches 4250mV, FC will not set.

Change all the JEita charging voltages to 4200

thanks
Onyx

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

Thanks onyx! I'll try that.

mike

0 mike zhang over 6 years ago in reply to mike zhang

Intellectual 925 points

Hi Onyx,
what is the re-start procedure? I don't why but after I changed the Jeita to 4200mV, updates status has been changed to 06 and Qmax cell 0 changed to 3234mAh.
the battery has been relaxed for more than 5 hrs since been fully discharged with C/7 rate. so I just issued a reset than IT enable command before charging at C/2 rate. now it is in charge state and got OCVTAKEN/VOK/QEN set and RUP_DIS cleared. is it ok for the re-start learning cycle?
Thanks!
Mike

0 mike zhang over 6 years ago in reply to mike zhang

Intellectual 925 points

Onyx, I don't know why the OCVTAKEN still remains SET. is it ok or not? thanks, mike

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

hmm if after making the changes you to Jeita, you had update status and qmax etc change, then it means learning must have been successful.
Any way to start afresh you need to take a new device, set the configurations per your settings and then run the learning cycle starting from discharge to empty after sending 0x21 (IT enable) and 0x41 (reset). You can also program the default srec which you can get from TI.com to get the device data memory in a pristine state

I would recommend you don't pay attention to OCVTaken or cleared. Just follow the procedure and i believe now you will have learning complete successfully since Jeita has been set.

OCV taken being set is actually a good thing because it means a valid DOD0 point needed for qmax update has been taken.

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

Hi Onyx,

the charge state was just done and OCVtaken was also cleared at the time, but FC has still not been set. i'm sure the charge voltage reached over 4.2V. there are still something not right. what should I do at this point? the log files attached for your review.

RegLog_chg_180321b_e2e.zip

based on your comment, in order to re-do the learning cycle on the device, I have to program the default srec from ti.com to the device. can you point me out a link where I can get the default srec and how to program it? that means for the device it is not possible to re-do the learning cycle for it without programming the srec to it after done an unsuccessful learning cycle. am I right?

thanks!

mike

0 mike zhang over 6 years ago in reply to mike zhang

Intellectual 925 points

Onyx,
seemed like RUP_DIS can't be set by issuing RESET command...

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

Hi Mike,
I am traveling so will not have the chance to review your files just yet. Can you send me a screen shot of the register window of bqstudio?
thanks
Onyx

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

Onyx,

here is the screen shot: I tried sending reset several times before or after issuing IT enable.

thanks,

mike

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

Hi Mike,
After sending the reset command, you need to click the refresh or scan button to see the rup dis flag set. Also, you need to have the scan flag checked so you can see if the FC flag gets set when charge termination is reached.

thanks
Onyx

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

Thanks Onyx.
ok it works for RUP_DIS but not for FC. how about re-do the learning cycle with the bq27742evm? do I have to reprogram it with that srce? if so where is it? thanks! mike

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

Hi Mike,

Yes pls use the evm and program it using the firmware downloadable from the link below

www.ti.com/.../sluc558

thanks
Onyx

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

Thanks Onyx!

to program the srec file to the evm with bqstudio, I need to do following steps:

open the programming tab;
select the default srec file by clicking Browse button;
program the srec file into the chip by clicking Program button.

is it correct? there is an other button called Execute FW in the programming tab. what to do with this button? do I have to click this button as step 4 in order to complete the programming process?

Thanks!

Mike

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

hi Mike
Yes the execute button is the final step. Then close bqstudio and restart.
thanks
Onyx

0 mike zhang over 6 years ago in reply to Onyx Ahiakwo

Intellectual 925 points

Thanks Onyx!

also, I was asked why I have to re-program the device? would you mind to tell me the main reasons why?

thanks!

Mike

0 Onyx Ahiakwo over 6 years ago in reply to mike zhang

TI__Guru* 76230 points

Mike,
So you can start with a brand new firmware as though it is a new chip
thanks
Onyx