Optimize settings: Dim the screen or turn on Auto-Brightness to extend battery life. To dim, swipe up from the bottom of any screen to open Control Center and drag the Brightness slider to the left.
Auto-Brightness adjusts your screen to lighting conditions automatically. To activate it, go to Settings > Display & Brightness and set Auto-Brightness to On.
When you use your device to access data, a Wi-Fi connection uses less power than a cellular network - so keep Wi-Fi on at all times. Swipe up to open Control Center, tap the Wi-Fi icon, and log in to a Wi-Fi network.
Background Activity: Go to Settings > General > Background App Refresh and set the switch to Off.
If the Mail app lists Background Activity, you can choose to fetch data manually or increase the fetch interval. Go to Settings > Mail, Contacts, Calendars > Fetch New Data.
Location and Background Location: You can optimize your battery life by turning off Location Services for the app. Turn off in Settings > Privacy > Location Services. Note: New data will be received when you open the app.
In Location Services, you can see each app listed with its permission setting. Apps that recently used location services have an indicator next to the on/off switch.
Home & Lock Screen: If an app frequently wakes your display with notifications, you can turn off push notifications for the app in Settings > Notification Center. Tap App and change the Alert Style to None.
No Cell Coverage and Low Signal: This indicates that either you are in a poor cell coverage area and your iOS device is searching for a better signal or that you've used your device in low-signal conditions, which has affected your battery life. You can optimize your battery life by turning on Airplane mode. Swipe up to open Control Center and tap the Airplane mode icon. Note that you cannot make
Plug in and power on your computer to charge your device: Make sure your computer is plugged in and powered on when you're using it to charge your iOS device via USB. If your device is connected to a computer that's turned off or is in sleep or standby mode, your device's battery may drain.