Turn Off Automatic App Refresh
Almost all the applications are programmed to refresh the content in the background or when the phone is idle, just to stay updated. This background refresh of applications is one of the major causes of battery drain. To disable background app refresh, go to Settings>>General>>Background App refresh. From here you can disable updates for all apps at once or individually for every app.
Note: Leave background refresh for apps that may need your regular location update so that your current location at all times can be accessed.
