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.

We set up the iPhone 3GS and 3G on the Crave Towers Wi-Fi network and set to streaming Leonard Cohen Live in London on BBC iPlayer.
Although we tired of the Canadian crooner after a couple of hours, the iPhones lasted longer.
The old boy 3G gave up with exhaustion after 3 hours and 2 minutes of classics such as Bird on a Wire and Hallelujah.
The young whipper-snapper 3GS toughed it out for exactly 5 hours of septuagenarian renditions of So Long, Marianne.
That's 118 minutes longer, or a 65 per cent improvement. Applause for the 3GS! And encores for Len.
Click through to see the how the phones handle the all-important 3G calling.

To test voice calling over 3G, we rang each phone from a landline and pumped the dulcet tones of Radio 4 through the receivers to simulate a civilised chat.
The older 3G stayed tuned to Woman's Hour for 2 hours and 35 minutes before giving up the ghost.
The fresh-faced 3GS lasted 3 hours and 48 minutes until it was completely discharged.
So 3G calling definitely drains those batteries, but the iPhone 3GS lasted 73 minutes -- or 47 per cent -- longer.

Click through to see how it all stacks up to Apple's iPhone promises.

Let's compare these values with Apple's estimates for battery life, shown in a hand-knit table.

Apple says these are maximum values, and don't forget that we had screen brightness turned up to max and everything turned on that could be turned on -- and our iPhone 3G wasn't new out of the box.

So maybe it's no surprise that our findings of around 2.5 hours of talk-time on the iPhone 3G and 3.75 hours on the iPhone 3GS are way below the max value of 5 hours that Apple claims.

And our test over Wi-Fi got us 5 hours on the 3GS, not 9 hours, and 3 hours on the 3G rather than the 6 hours advertised.

With over 45 per cent improvement over the iPhone 3G in both our tests, the iPhone 3GS lives up to its claims of battery superiority. And it's interesting to note that the 3GS out-performs its older cousin even when Apple says that the talk-time over the 3G network is the same.

Our American cousins over at CNET.com did a straight talktime test on EDGE, and managed almost 11.5 hours of battery life, compared to the iPhone 3G's results of 8.75 hours.

The upshot is that yes, battery life on the iPhone is diabolical... but it's significantly better on the iPhone 3GS. So if you're pondering whether it's worth the investment in the £100-more-expensive 3GS, consider how long you're likely to spend away from the plug.

You should also check out our comparison of the twin iPhones' other features to help you choose.

And whether you decide the future is now with the iPhone 3GS, or kick it old-school with the iPhone 3G, you'll need Apple's tips on how to conserve battery life. Who knew? All you have to do is turn all the good stuff off.