Other Parts Discussed in Thread: GPCRB, BQSTUDIO, GPCCHEM
We have a mature product that uses the bq2751G1 gas gauge. We recently had a return from one of our customer because the SOC on the batteries were at 0%. After some experimentation, I found that they are shifting from approximately 30%SOC to 0%SOC when temperature drops to about 7°C. I have done a comparison of flash settings to both an exemplar battery that does not exhibit the failure mode and to the golden file and found no unexpected differences. I also dropped temperature from ambient to 0°C while monitoring HDQ on one batter, which is how I found that it is dropping at around 7°C. There is no indication of anything except at that point, where RM goes to 0, driving SOC to 0 and setting SOC1 and SOCF.
When the SOC drops, voltage is still at what would be expected at approximately 30% SOC, not what would be expected at 0% SOC. Cycling the battery resets SOC to the proper value. It does not reset when temperature rises again.
There have been no board changes or programming changes. I could find no mechanical reason for this failure, and can find nothing in the tech ref that would explain this reaction. Can you point me in a direction to look?
