BQ20Z75-V180: BQ20Z75-V180 shows incorrect SOC on a fresh pack

Larry Norman

Part Number: BQ20Z75-V180

I have a pack model using the BQ20Z75-V180 and Panasonic UR18650A cells. Packs in previous builds would "wake" at around 50% RSOC. Panasonic is now shipping these cells to be compliant with the new transport requirement to be "less than 30% SOC" for air transport.

The cells in my most recent production lot measure around 20% SOC when discharged, however, when the pack "wakes up" it is showing 0% RSOC.

Is this because it does not like the OCV that it sees when it wakes up? If so, is there any way to change this?

Thanks,

Larry

over 7 years ago

0 Larry Norman over 7 years ago

Intellectual 855 points

Any help here?

Thanks,

Larry

0 Swaminathan Ramanathan75031 over 7 years ago in reply to Larry Norman

TI__Expert 6575 points

Hi Larry,
Can you send me the gg file from one of these packs? Also, can you tell me what chemID you are using, and the voltage of the cells when the pack is exiting shutdown, I can check to see why it might be coming up with a 0% RSOC.
Regards,
Swami

0 Larry Norman over 7 years ago in reply to Swaminathan Ramanathan75031

Intellectual 855 points

Hello Swami,

Thanks for the reply.

This is a 4S pack and the cell stack is around 14.4V when the packs are waking up.

Chem ID is 0252

file sent via email

0 Larry Norman over 7 years ago in reply to Larry Norman

Intellectual 855 points

Hello Swami,

Thanks for your assistance.

The Chem ID in my golden .dfi / .rom files is 0252, but the chem ID in the production packs is the default 0100. Apparently, our PCBA manufacturer loaded the .gg file instead of the .dfi / .rom file.

We are resolving the issue by manually updating the Chem ID and then importing the golden .gg and preserving the calibration. The RSOC comes up to the expected value of 20% ~ 25%.

Thanks again for your help.

Larry Norman

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BQ20Z75-V180: BQ20Z75-V180 shows incorrect SOC on a fresh pack