How to improve battery life on the iPhone 3G

I mentioned in my blog over the weekend that I was frustrated by the fact that many iPod accessories won't charge the Apple iPhone 3G - and alluded to

Well, a bit more experimenting has confirmed my fear that the out-of-the-box configuration of the iPhone 3G has disappointing battery life - use it heavily (as you undoubtedly will) and it won't even see you through a day.

Fortunately, there's a simple solution that I was alerted to by a colleague (cheers Mark). There are two steps:

1) Reset your iPhone's settings. Do this by going to 'Settings/General/Reset'. This won't delete anything too important, although it did remove my Exchange email settings (though fortunately not the security certificate I need to access the Microsoft Exchange server).

2) Turn off 'Location Services'. This essentially de-activates the GPS, thereby doubling your iPhone's battery life.

There are other things you can do to improve battery life - make sure 'Auto-Lock' is set to '1 minute in 'Settings/General', and reduce the brightness of your screen in 'Settings/Brightness'. The iPhone 3G's screen is noticeably brighter than the old iPhone's so you're not losing anything by doing this - and you can always boost the brightness if and when you need to.

UPDATE Apple also has an official battery optimisation page here.

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