I think it has to do with iOS 11. I have tried updating to latest 11.2.1, but it did not help, also tried backup, reset, and restore did not help. Does anyone have a solution?
- I should mention that I took it the Apple store, and they did not find any issues. They recommended backup, erase and restore.
- Also take a look as this user suggest the issue is iOS 11 - https://discussions.apple.com/thread/8101649
- I downloaded app that show battery capacity status - it is 1400/1570mAh 89%, this means its not a battery issue.
- Went again to apple store to ask to try replace battery and see if that help. They did full test again, and said it seem like software issue, all hardware is in great condition. And they recommended reset without restore. We did full reset and I did not install any apps, and the issue is still not resolved.
- I bought a new battery from iFixit. It did not resolve the issue. I did notice that switching to low battery mode does help reduce the random shutdowns, but not completely resolve it. I guess my solution is switch to android device.
I believe that if apple would allow switch back to iOS 10.3.3 , then that would probably have resolved it. I assumed the latest iOS would be better, but probably not for older models.