Sounds like calibration. It gets really bad the older it gets. My 5's battery will be at 22% and my Wife calls via FaceTime. Within 30 seconds, the screen goes black with the little wheel spinning. I'd suggest letting it run down to 1% , then charge it up to 100% and then some without using it along the way. I say and then some because at 100% it's not fully charged. Think your car's gas tank. When it gets to Full, you can still add more gas.
Sent from my ancient but trustworthy iPhone 5. ☮
04-06-2015 01:54 PM