Submit secondary cells for ChemID characterization

the bq27520 was not designed to be used with primary cells, except you want to use it as a coulomb counter. How do you plan on using this device?
thanks
Onyx

Thanks for the reply. 

I'm looking at a rechargeable LiCo or LiMn single cell.

Cell is  labeled as AW. Its a 550mAh CR123 LiMn 4.2 volt rechargeable. Right now I'm working with this LiMn, but might switch to the LiCo at 750mAh.

Hi Chris,
The subject of your post said said primary cells hence the confusion. There might be no need to submit your cells for characterization as it might have either been characterized in the past and might be in our data base already or there might be a match with an already existing chem id in the data base. See link to tool below that explains step by step process on identifying a match.

www.ti.com/.../gpcchem

thanks
Onyx

I did that. First time I've gotten a success out of the tool. Last time I had a little blip in my discharge.

What is confusing for me, all the documentation that I've read points to C/5 discharge rate. bqEasy too. My battery is not in the list. 

Yet the report wants something even less. 

I hope its okay to post the report here

hi Chris,
I hope you found the crash course helpful. Let me know if you run into any further issues.
thanks
Onyx

I have become much more familiar with the process. I still don't have a ChemID match under 3% however.


I am redoing the bqEasy Chemistry cycling at a C/10 rate and will report back. After that I'd be very interested in sending in my secondary cells if I still don't get a match under 3%.

Using the default LiCo chemistry I was able to complete a full learning cycle the other day. First time I'd gotten all the way to update status 02 without RUP_DIS enabling during discharge. Ra Table updated and did not fill with negative values. So I do have a golden image, but just with the default chemistry.

However my battery is not LiCo but LiMn. I suppose if the learning cycle worked, its good enough.

Thoughts.

If learning was successful, update status will be 06 not 02. update status of 02 is for system side gauges. the bq27742 is a pack side gauge and not a system side gauge.

if you were able to get update status to be 06, the best way to determine if it is good enough is to cycle the battery after learning and  evaluate the gauge for accuracy. Pls review the attachement and calculate the accuarcy of the guage based on the steps described in the ppt. if you are still unable to send a match you will have to send the cells to Dallas for characterization. This process takes between 4-6 weeks.

3872.Analyzing Accuracy of a Battery Fuel Gauge System - Onyx Ahiakwo Jared Casey.pdf

thanks

Onyx

Will do Onyx.

I thought I was looking for 02. I am working with the bq27520-G4, which is system side.
I'll do an accuracy test.

Thanks! (for the information)

I apologize , i thought it was the bq27742 you were using. Since you are using the bq27520 which is a system side gauge and you got an update status of 02, it means learning was successful. You should now cycle your battery and carry out accuracy calculations as per the ppt i attached.

cheers
Onyx