iPhone 6 weird battery percentage issue. My iPhone 6 running iOS 9.3.1 will go from around 48% battery down to 12% in a split second. It has done this several times on the past and then as soon as I plug it into power, the phone will go back up to its 48%. If I keep using it without plugging it in, it will die within 10 minutes or so. Is this a battery calibration issue? I have tried calibrating the battery in the past where I charge it to 100% and then let it run down until it shuts off and then charging it to full again. Any help is appreciated!











