Well, I bought a 8310 on Craig's list and the phone was all sealed, look brand new...stickers, everything. I've had it for month now and works great...even upgraded the O/S. Today it cut out on me dead....I used charger in car to about 50% and after a call it went dead. I plugged into home charger and it came up with about 30% on battery. I looked at battery C-S2 and on side/edge there is small xxxx. Do these mean battery has gone bad ?

Any inputs ?

I think the xxxx is normal. While rare it is possible you have a bad battery, or charger or even the female mini usb connector. Only way to know is to experiment with another battery or charger. Note: There are some 3rd party programs that use alot of power!