iPhone 3GS vs iPhone 3G real-world battery test: Over 45 per cent better

Sure, smart phones such as the iPhone can order your groceries and hail you a cab, but they eat batteries like a fat kid let loose on the pick-n-mix.

Apple promised that the new iPhone 3GS would improve things with better battery life, but we're the kind of rugged individualists who have to see things for ourselves, so we took an iPhone 3GS and and iPhone 3G into our hermetically sealed lab deep in the antarctic tundra -- okay, a desk in the corner -- and set them two gruelling tasks.

First, to get the lithium-ion batteries really sweating, we turned the screen brightness up to maximum, turned off the sleep function so the screens would stay on, and turned on Bluetooth.

We charged both phones to maximum and then let it rip. Tests were recorded with a laughably small video camera on a ridiculously big tripod, to ensure we caught the very moment of exhaustion.

Note that our iPhone 3G has been faithfully working for the past six months, so its battery isn't as fresh as the iPhone 3GS we used.

Click 'continue' to see the how the phones handle streaming video and Wi-Fi.

Update: Flora, who has a degree in physics, got the percentage improvements wrong in an earlier version of this article. She has fixed them and feels very ashamed of herself.