bq34z100 voltage divider and what happen if power will be switched off

Dmitriy Olympiev

Other Parts Discussed in Thread: BQ34Z100, BQEVSW

Hello!
I use a 12s2p 10.2Ah lipo battery with 50400mV (12*4200mV)
maximum voltage. I have to define it chemistry ID because "E-
Stars 1143128 5100mAh" cell isn't present in Chemistry selection
table. I don't use evaluation board, so Evaluation Software too.
According to this forum, I can define chemID by using
"Identifying unknown chemistry simple discharge test – 24 hrs"
or your help, BUT bq34z100 measures Voltage of the pack not
properly.
My Rseries=976k with bottom R=16.5k and parameter of the Voltage
divider was 50400mV.
First, I thought the problem is in Rseries and I changed
parameter of the Voltage divider to 54136mV to reach 900mV, but
bq34z100 measures Voltage not properly again.So the question is:
what isn't right with Voltage measuring in my case?
And the second question, what would happen with all of this
calibrations, SOC, RM etc. if power of bq34z100 will be switched
off?

Thanks a lot

over 9 years ago

0 ThomasCosby over 9 years ago

TI__Guru 73830 points

It looks like you have the voltage divider setup properly and the Voltage Divider is in the proper range. You can try using the manual voltage calibration technique, since you do not have access to the bqEVSW. It is described on page 10 of the Going to Production document. It is available in the bq34z100 product folder.

If the device is switched off, then it will run an FCC simulation after the voltage is restored. The simulation will estimate the capacities based on the OCV table.

0 Dmitriy Olympiev over 9 years ago in reply to ThomasCosby

Prodigy 50 points

Hello, Thomas!
Thanks for your answer!
I decided to use evaluation board and evaluation software, so can you help me with chemID? Log-file is in attachment.

Some notes to this log:

1. Charge current isn't in log by my mistake. It was about 1100 mA (0.1C)

2. Relax time after discharge is more than 5 hrs (5 hrs of relax end at 3:10 am)K4_chem_ID.log

0 Dmitriy Olympiev over 9 years ago in reply to Dmitriy Olympiev

Prodigy 50 points

Hello, Thomas!

If I need to correct my log, please tell. I rewrite it. Thanks a lot!

0 ThomasCosby over 9 years ago in reply to Dmitriy Olympiev

TI__Guru 73830 points

Dmitriy,
We could not find a match for your battery in our ChemID portfolio. If you would like to submit cells for characterization, then please provide an email address and I will send you the information to submit.
Tom

0 Dmitriy Olympiev over 9 years ago in reply to ThomasCosby

Prodigy 50 points

Hello, Tom!
My email is in my profile.

0 Dmitriy Olympiev over 9 years ago in reply to Dmitriy Olympiev

Prodigy 50 points

Hello, Thomas!
Could you tell me the closest chemID to my battery if it possible while the characterization process would be in progress?

0 ThomasCosby over 9 years ago in reply to Dmitriy Olympiev

TI__Guru 73830 points

Dmitriy,
The program did not yield any candidates. I checked several ChemIDs and all of them had OCV table excursions below the discharge voltage. That is a peculiar battery.
Tom

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bq34z100 voltage divider and what happen if power will be switched off