Hello
I have had a lot of battery cells coming back from customers that are 1) not able to charge, or 2) the cells are completely drained. The battery has been in production from at least six years, and we have not seen so many failures come back. DVDD is wired to enable the charge function of the device and sets the cell count to 3. I have disconnected the controller board from the cells and have hooked it up to a power supply to 'mimic' a battery sans the two middle connections. What I have been finding is that the DVDD ouput is either at 0V or about 1V. The difference between the two is when DVDD is at 0V the battery cells have a fair amount of charge on them, but they cannot be recarged. When the DVDD output is at 1V the device will draw between 60 and 70mA of current, which means that a low impedance has formed some where in the part. The date codes on the part are from 95V and 96V. Has anyone seen this type of failure, where is the part failing internally, and what is the cuase?
Thank you!
Bryon Czaja