Hello, it's strange that I am having the exact same problem as you. I guess doing a search before asking helps...I will post a description of my problem in conjunction with this thread as it appears we may be experiencing the same difficulties.
Over the last week or so, I've had days where the phone would charge fine, and other days where the phone would not charge at all, or would quickly lose battery life. This morning was the worst so far. From a full charge the phone lost 100% battery life in just over an hour. I tried a hard reset as a last ditch effort. The phone is now dead and although it is plugged in with the red charging light, it will not even turn on. If it does manage to get to the home screen it immediately states that it will shut off due to the battery being dead.
I am not sure what to do as the battery works fine some days, and doesn't function at all on others. Is this a normal process for a dying battery? I would assume that it would just slowly deteriorate without any gain in functionality. I can't imagine a rogue app being the reason for the problem as it still exists after a hard reset.
Am I going to have to get a new battery? Should I bring it in to a phone repair shop? Does anybody know what the hell is going on!?
Thanks!