Compatible with iOS 8
Also try, ChargingHelper (iOS 6 & 7)
It can show you the remaining time while your device is charging .
It also can remind you when the charging is complete.
It even can pop the battery information if you want to know.
Importantly, it is a iOS 8 compatibility tweak.
Maybe you know the ChargingHelperPlus, it is a lite edition for that.(No app on screen).
After install. you should do:
1.go to settings and check the ChargingHelper option.
2.ues it well.