BQ40z50-r1 battery pack becomes unusable for no reason (FUSE on and CHG/DSG FET off)

Long Pham67

Other Parts Discussed in Thread: BQSTUDIO, BQ40Z50-R1, BQ40Z50

Hi,

Out of the 5 battery packs that I’m testing, two packs have FUSE turned on and DSG and CHG FET turn off, for no reasons. The packs have gone through a few charge/discharge cycles. PF status and safety status are all inactive.

I’m wondering why the permanent fail FUSE is on and CHG/DSG FET are off. And how to prevent this situation?

The two packs are unusable when DSG/CHG fets are turned off.

Thank you very much for your help!

Long

FYR, I put the srec file here:

https://drive.google.com/open?id=0B8RgADdsXT_DUmtYSjAwal9tYnc

bqStudio screen shot: http://imgur.com/a/RWLtt

over 8 years ago

0 Damian Lewis over 8 years ago

TI__Mastermind 34775 points

Hello Long,

Let me look into your concern and get back to you.

0 Damian Lewis over 8 years ago

TI__Mastermind 34775 points

Hello Long,

What cells are you using? Can you bypass the DSG and CHG FET with a wire on the packs that failed to re-establish communication with the gauge and get the srec or gg.csv file?

I can't tell from your srec you provided what went wrong. I downloaded the srec to my EVM and it looked fine. OperationStatus()[FUSE] = 0, which was different from your screenshot.

0 Damian Lewis over 8 years ago in reply to Damian Lewis

TI__Mastermind 34775 points

Hello Long,

Do you have a secondary protector device on your PCB? If so the secondary protector may have initiated the FUSE blow and the bq40z50-R1 detected that the FUSE blow was initiated then disabled the CHG and DSG FETs. The FUSE pin on the bq40z50-R1 is also used by the gauge to monitor the state of the gate of the fuse blow NFET in order to detect if the fuse was blown by the secondary protection device.

0 Long Pham67 over 8 years ago in reply to Damian Lewis

Prodigy 50 points

Hi Damian,
Yes I do have bq296103 as a secondary protector.
I guess something's wrong with the BQ40z50 chip. After replacing Bq40z, everything works well.
Thank you very much for your answers.

Best Regards,
Long

0 Damian Lewis over 8 years ago in reply to Long Pham67

TI__Mastermind 34775 points

Hi Long,

I'm happy to hear you got the pack working. What set up did you use to communicate with the pack? EV2300 and bqStudio? If so what version is the EV2300 used firmware?

0 Damian Lewis over 8 years ago in reply to Damian Lewis

TI__Mastermind 34775 points

If there version is 3.1c, you should update it to 3.1r. I've had 3.1c render a few of my bq40z50-R1 unresponsive and had to replace the device.

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BQ40z50-r1 battery pack becomes unusable for no reason (FUSE on and CHG/DSG FET off)