Some user claims about iPhone 6 and 6 Plus that keep restarting and not. Mobile working fine before after low battery shutdown problem created. Try all troubleshooting steps but same issue. if you tried tried all Steps Restore iPhone with iTunes, Download Latest Firmware, Putting iPhone into DFU Mode or Recovery Mode, Pull Out Your SIM Card, Restore iPhone with iTunes, and problem not solved then its hardware issue. We can solve this issue by using some methods. But remember if you able to find nearest apple store to get your iOS device repaired by the high-tech team of Apple technicians then its better option for you.
- Force shutdown your iPhone 6 or 6 Plus by pressing power button and home button for 15 to 20 seconds.
- Connect iPhone with original charger for 3 to 5 hours.
- Clean mobile charging port with cotton and electronics cleaner.
- Check your mobile charger on other mobile.
- Final solution Replace the battery.
I Repeated again if you not able to fix your iPhone , then bring your iPhone and charger to the iPhone warranty center. The technicians there will help you fix the iPhone.