PC World compared the battery life of the iPhone 4 and iPhone 3GS
As you know, Apple's new iPhone 4 boasts a boatload of new features and improvements. One such improvement is increased battery life. Apple claims the new phone can outlast its predecessor by an hour in Internet use, two hours in talk time, and 10 hours of audio playback. Both the iPhone 3GS and iPhone 4 claim to hold enough juice to play up to 10 hours of video, and can last up to 300 hours in standby mode.iPhone 4 Battery Life: The Test Results Are In
To get an idea of how the iPhone 4's battery life compares to its predecessor in varied use, I borrowed a colleague's year old 32GB iPhone 3GS and tested it and the iPhone 4 using a series of different tasks. The results show that the iPhone 4 does indeed last an appreciably longer time.
