One of the biggest drawbacks of the iPhone 3G is that the battery cannot be removed or replaced, which becomes frustrating once you realize how much power the iPhone uses. If the iPhone is your primary phone, you’ve got to tether it to an electrical outlet at least once a day. There’s really no other choice but to deal with what you have, but there are ways to increase the battery life of your iPhone 3G.
Lower the brightness
As with any device, the LCD screen backlight of the iPhone sucks out a lot of its power. If you’re indoors most of the time, make your screen as dim as you can stand by turning off the Auto-Brightness setting and adjusting the brightness.
Avoid extreme heat
The iPhone uses a lithium ion battery, which is sensitive to extreme temperatures. Any temperature above 114 degrees Farenheit can degrade the batter and will translate to less battery capacity in time.
Turn off the Bluetooth when not in use
A wireless headset is the only device the iPhone’s current firmware can support. Unless you use the headset all the time, turn the Bluetooth off to save on power.
Turn off Push
Unless it’s absolutely necessary that you get notified of new emails right when you receive it, change your email settings by turning off Push on your iPhone. Push is less expensive as checking email the usual way, but it can suck battery power if left on all the time.
Turn off 3G
Unless you’re using the Internet, you probably don’t need the speed of a 3G connection, which consumes more power than the EDGE network. You can turn off 3G by going to Settings > General > Network. Find the setting that says “Enable 3G” and switch it off.
If all else fails…
Always keep an iPhone USB cable in your bag or purse, and a power adapter in your car if you have one.