Hi all -- The past few months my iPhone 5 has been shutting down (to the charge screen if I try to turn it back on) when the % meter shows anywhere from 10-20%. What's even more confusing is that as soon as I plug it in to charge, it turns back on, and may even continue draining normally from there (from the 20% all the way to 0%). Perhaps a related problem, I've had times where the battery was at 9%, then ticks normally to 8% and then suddenly drops to 4%. Any ideas? The first problem is more troubling.