Other Parts Discussed in Thread: BQSTUDIO
Hi,
We have been using the BQ40Z50-R1 for several years in a number of consumer electronics for our BMS solution. It has performed as expected fairly reliably in an expected fashion until recently. Our design and test teams have begun experiencing a new behavior that we can't explain. Our applications are various types of energy storage systems with integrated charge controllers and power conversion for multiple outputs. A central MCU communicates with the BMS IC and several other peripherals. In the last 2 weeks, we have started seeing the following behavior from units that previously performed as expected:
- A load is connected to the ESS that creates a 1C - 1.5C discharge from our pack
- The unit discharges normally for several minutes
- The display on the product shows the state of charge begin to decrement at a rate of approximately 1 percent per second until 0 is reached.
- After a long period, typically 1-2 hours, the state of charge returns to the expected value
We have several captures from Battery Management Studio showing the state of the battery after 0% SoC is reached:
As well as after recovery:
One thing we've noted is that the charging and discharging have been disabled in OperationStatus (XCHG and XDSG). We're continuing to look into this but are hoping one of the experts here can speed us along the way to understanding and resolving this. Also included are the gg files from immediately after the event and after the pack has resumed normal operation.
Please let me know what other information might be helpful in diagnosing. Thanks in advance!
Sterling