Why does battery life go down when it is switched off overnight and plugged in to charge

[AC Question]

Sometimes it is fully charged by the morning but other times it less charged than the night before.

 

[srkmagnus]

Sometimes it is fully charged by the morning but other times it less charged than the night before.

You could have an app running and using resources in the background. Can you take a look at the running apps and see if anything sticks out? If something is running unusually high then that could be the culprit.

 

[Golfdriver97]

Since the device is off, I would look at the cable and wall plug. Try different ones. If the problem still persists, it may be the USB connection in the phone.