BQ27426: SOC is not accurate

Zach Zhu

Part Number: BQ27426
Other Parts Discussed in Thread: BQSTUDIO

Tool/software:

Hi expert,

My customer encountered a problem when using BQ27426. Pls refer to comments as below.

At the beginning we will load the golden image
Then read the battery voltage and SOC
But found the same machine
The battery voltage is very accurate
But the SOC difference is huge
What conditions are needed for the SOC to be more stable after reading the golden image?
Why is there such a big difference?
Is there any documentation or recommended testing method?
The following are the test results of two consecutive tests on the same machine

1. Vbat=3.981V, SOC=58%

Vbat=3.985V, SOC=73%

BR,

Zach

5 months ago

0 Alan Frias 5 months ago

TI__Mastermind 26265 points

Hello Zach,

What software are you using with BQ27426? We recommend using BQStudio.

BQStudio:
https://www.ti.com/tool/BQSTUDIO

Thank you,
Alan

0 Zach Zhu 5 months ago in reply to Alan Frias

TI__Intellectual 1560 points

Hi Alan,

Thank you for your support!

RD used BQSTUDIO to complete the golden image
Then during production, after the whole machine is assembled, the gauge will not be powered off.
Load gauge golden image command for the whole machine
Then read the gauge voltage and SOC
The problem I mentioned appears, the same Vbat but the SOC will be very different
Is there any aspect of this process that needs to be modified?
Or is there any suggested approach?

BR,

Zach

0 Alan Frias 5 months ago in reply to Zach Zhu

TI__Mastermind 26265 points

Hello Zach,

Can you attach a .log file of the event in question along with a .gg file as well.

Thank you,
Alan

0 Zach Zhu 5 months ago in reply to Alan Frias

TI__Intellectual 1560 points

Hi Alan,

How can RD obtain .gg and .log?

BR,

Zach

0 Alan Frias 5 months ago in reply to Zach Zhu

TI__Mastermind 26265 points

Hello Zach,

For a .log file you would need to pressure the "start log" button in bqstuido shown below and recreate the event and click on "stop log" in order to view your registers. As for the .gg file you can export it within the Data memory tab.

Thank you,
Alan

Power management

Power management forum

BQ27426: SOC is not accurate