So I left my iPhone 6 charging while I slept, but when I woke up to turn off my alarm, I noticed that it was only 87% charged. I left it on while I got up and ready but it didn't change at all. Any ideas why?
It may just need calibrating. Run it down until it shuts off and reboots. Then let it charge to 100%. When it gets to 100%, let it charge another 20 minutes. Don't use the phone while it's charging. If that doesn't work, try Reset All Settings. Go to Settings >General >Reset >Reset All Settings.