Update to the latest software.
Always make sure your device is using the latest version of iOS.
If you are using iOS 5 or later, see if you need an update. Go to Settings > General > Software Update.
If an update is available, you can plug your device into a power source and update wirelessly or plug it into your computer and update with the latest version of iTunes.
Optimise your settings.
There are two simple ways you can preserve battery life — no matter how you use your device: adjust your screen brightness and use Wi‑Fi.
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 Centre 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 mobile network — so keep Wi‑Fi on at all times. There are two ways to turn on Wi‑Fi:
Swipe up to open Control Centre, tap the Wi‑Fi icon and log in to a Wi‑Fi network.
Go to Settings > Wi‑Fi to access a Wi‑Fi network.
View Battery Usage information.
iOS 8 is designed to be the most battery-efficient iOS ever. And it gives you more precise ways to manage your device’s battery life, because you can see the proportion of your battery used by each app (unless the device is charging). To view your usage, go to Settings > General > Usage > Battery Usage.
Here are the messages you may see listed below the apps you’ve been using:
Background Activity. This indicates that the battery was used by the app while it was in the background — that is, while you were using another app.
To improve battery life, you can turn off the feature that allows apps to refresh in the background. 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. This indicates that the app is using location services.
You can optimise your battery life by turning off Location Services for the app. Turn off in Settings > Privacy > Location Services.
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. This indicates that the Home screen or Lock screen was displayed on your device. For example, the display was awakened by pressing the Home button or by a notification.
If an app frequently wakes your display with notifications, you can turn off push notifications for the app in Settings > Notifications. Tap App and set Allow Notifications to Off.
No Mobile Coverage and Low Signal. This indicates that either you are in a poor mobile 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 optimise your battery life by turning on Airplane mode. Swipe up to open Control Centre and tap the Airplane mode icon. Note that you cannot make or receive calls while in Airplane mode.
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. Note that iPhone 3G and iPhone 3Gs cannot be charged with a FireWire power adapter or FireWire-based car charger.
