Some background programs break, go wild, and waste your battery. So, while your iPhone may appear to be charging slowly, the background apps are rapidly depleting the battery. You may force all running applications to close or turn off your iPhone while charging in this situation.

1. Quickly press the Home button twice. This brings up the Apps viewer screen, which displays a list of recently used apps. These apps are in the background and in standby mode.
2. To end the app's preview, swipe upon it.
3. Carry on with the remainder of the background programs in the same way.