Q: Question for golden sample image with lower charge condition by 1407300

Dear all,

I have one question on golden image creation for bq20z70 and bq20z45 gauge.

If i lower the charge voltage from 4.2V to 4.1V, Qmax and update status shows wield value. for example, Qmax update to 2650 for 2550mAh cell, and update status doesn't update. If charge voltage is changed back to 4.2V, all value is back to normal.

Also, if i use this golden image with 4.2V cahrge voltage on creating one pack with 4.1V charge voltage, FCC show big difference between each learning cycle. FCC change also affect RSOC, and RSOC jump can be detected.

Does any body have any idea how to create golden image with 4.1V charge voltage?

 


Q: Re: Question for golden sample image with lower charge condition by 1270005

Hi Tao,

i have exactly the same problem, my chip is a bq78pl114, but behaves exactly equal in this points.

With the bq78pl114 this seems to belong to the .chem file. TI has to provide me an adapted chemical file for the lower charge voltage.

If this is true for you, you have to send TI a couple (2..3) of factory fresh cells and they can provide you the correct chemical file. Ask them for shipping address.

What cell are you using?

Why do you reduce to 4.1V?

 

Regards

Andreas

 

 


Q: Re: Question for golden sample image with lower charge condition by 1407300

Hi, Andreas,

thanks for your solution. actually, TI has another solution for lower charging voltage without change cehm. ID or others. just adding more step for golden image creatation. of course, this procedure is suitable for any cell.

1. do the regular  golden image procedure (using 4.2V for charge voltage)

2. after discharge to 0% RSOC, charge to full by 4.1V

3. rest more than 35 minutes (this is imprtant, let gauge to update its dod_charge)

4. discharge by 1 minute

after above steps, you may export your golden image by regular procedure.

by the way, lower charge voltage can improve cell's lifetime

http://www-k.ext.ti.com/SRVS/CGI-BIN/WEBCGI.EXE/,/?St=20,E=0000000000016679981,K=7335,Sxi=0,Case=obj(47851)

 

Tao

 


Q: Re: Question for golden sample image with lower charge condition by 1270005

Hi Tao,

that does not work here, i tried this already and get a jumping RSOC

 

Andreas

 


Q: Re: Question for golden sample image with lower charge condition by 550568

Andreas,

bq78PL114 is different than the impedance track devices in terms of golden learning. The z-track devices always use the same chemistry files, but require the procedure mentioned by Tao above to work with lower charging voltage. Hope this clarifies it a bit.