For several months now, my iPhone randomly dies when it has a sizeable amount of battery left. Today for example, it died with 24%. I couldn't turn it back on because it said it needed to be charged. Ten minutes later it allowed me to turn it on. It then said it had 21% and shut off instantly. Two hours later (without charging it) I managed to turn it on again. 11%. Used it on a metro ride until it hit 5% and it shut off. Other times it's died with ~15% and I've never been able to turn it back on until charging. Sometimes it happens around 5%, but one time it happened with ~35%. Has anyone else experienced this problem? I honestly can't remember if this was happening before I updated to iOS 9. I recently enrolled in the beta program and am running Beta 3 of iOS 9.2 (I think that's the version). I do know for sure that this was an issue long before I signed up for that.