Part Number:BQ78350
We're having a problem with a BMS BQ78350 gas gauge paired with a BQ76940 analog front end connected to a 14 cell pack. The problem is that we had a working serial production battery pack that seemed to be working fine. We had an "unknown event" that tripped the BMS protection and opened the protection FETs. It's likely that it was an over current event, but I don't know that for a fact at this point. When the pack was removed from the system, the BMS will not recover and will not close the charge or discharge FETs.
Things we've tried:
Connecting with battery management studio doesn't show any obvious issues:
We've tried resetting the BQ76940 with the boot button.
We've tried manually controlling the FETs by issuing the FET_EN command followed by a 0x001F (CHG FET) and 0x0020 (DSG FET) with no results.
Can someone help point me in the right direction with regards to:
- What would be some common problems that would cause a working pack to exhibit this kind of failure?
- It there anything in Battery Management Studio that will tell us what's going on with the BMS and why it won't close the FETs?
- Is there anything we can set/reset through the Battery Management Studio that would reactivate the normal operating mode?