Apple provides a webpage that offers an overview of the battery life of the iPhone. Apple also rates the iPhone 4 battery life out of the box:
iPhone 4 offers up to 7 hours of talk time on 3G, 14 hours of talk time on 2G (GSM model only), 6 hours of Internet use on 3G, 10 hours of Internet use on Wi-Fi, 10 hours of video playback, or 40 hours of audio playback on a full charge at original capacity. In addition, iPhone 4 features up to 300 hours of standby time.
The most significant draw of battery life on an iPhone is the display. Games put a heavy load on the graphics processor of your device, and the easiest way to drain your battery is to play a game with heavy graphics. If your battery is low, don’t play iPhone games.
The following can all be disabled within the iPhone Settings app:
- Networking: 3G and Wi-Fi pull a lot of juice from your battery. To maximize your iPhone 4 battery life for calls and text messages, disable networking and only turn it on when you need it.
- Location Services: The iPhone’s GPS is constantly transmitting and receiving information. Disable Location Services and your battery will last longer than by keeping it enabled.
- Bluetooth: Typically, Bluetooth is used for headsets or hands-free activity within a car. If you don’t use these or can temporarily do without, disable Bluetooth on your iPhone. It may be enabled and you don’t even realize it.
- Vibrate Mode: When your iPhone vibrates, small motors inside the device must physically move it. Enabling vibration on your iPhone requires more battery power than a ringtone from the speaker. Disable it unless it’s absolutely necessary.
Minor Battery Drains
These adjustments will not add significant life to your battery, but they can deliver a few more minutes in every charge cycle:
- Volume: Lower the volume on your iPhone 4 and the battery will need to drive the speaker with a little bit less power. Perhaps the easiest of all these options to adjust, since you can use the volume toggle switch on the side.
- Brightness: To maximize battery power using brightness settings, disable “Auto-Brightness” and slide the brightness control to the lowest limit your eyes allow. You may need to adjust under different lighting situations, which is what the Auto-Brightness function also does.
- Push Notifications: Every time you receive a push notification on your iPhone it drains the battery very slightly. A single push notice may be a negligible drain, but if you receive multiple push notifications every day, your battery life will suffer. Disable push notifications for all apps which are not an absolute priority, or temporarily disable them when your battery is low.