My iPhone powers down because it claims to have run out of juice. After I plug it into a charger and then take out the charger my battery bar goes to 30%. 0% to 30% in a few seconds. After I take out the plug it can still stayed powered on for a few minutes but then dies down. Is my iPhone messed up? What's going on and anyone else experiancing this? BTW no background apps other then iPod and things like that.