I have an issue...not a horrible one but a curious one. Whenever my battery gets down to 15% the phone phone will usually shut itself down completely like the battery is empty. Screen just goes black...no power down just immediately off. The reason I say usually is that once in awhile it will actually not do this and keep the phone working until around 5-8%. That is a rare occurrence though as usually at 15% it dies. I have 2 batteries so it can't be the battery unless its both of them. Anybody else notice this curiosity? Is it maybe a safety feature to save the battery from completely draining or a setting in an app I don't know about that may be causing it?