Chosen Solution
After successfully replacing my iPhone 5 battery by following the guide on here, I turn on my phone to see that everything works as normal. (The battery showed 66%) After plugging it in for the night soon after I wake up to see the battery still shows 66% (my phone showed it was charging when I plugged it in). After turning it off and turning it back on it showed 100%. Now, throughout the day’s use, the only way I can see the “accurate” battery percentage is by turning off the phone and turning it back on. I don’t understand how this can be. Any help would be great!
That sounds like a bad battery controller to me. Unfortunately, I’m not sure if the controller is part of the battery or if it’s on the main logic board. Usually it’s on the battery itself, but having looked at these batteries I can’t figure out where. If I’m right, and the controller is on the battery, you just have a defective one. The only other thing I would recommend trying is restoring you phone.
Look here: Check your serial number here to see if it qualifies for the Battery Replacement Program: https://ssl.apple.com/support/iphone5-ba…
