ITWire

A flat battery in a media player is little more than an inconvenience, and it's no big deal if there's some extra work needed to change a battery when it won't hold a charge after a few years use.

Most of the first hand reports we've heard about the iPhone say that one charge lasts at least a day in normal use, so there's rarely any need to swap batteries (assuming that you could). Being without your phone while the battery is replaced is a bit of a drag, but most households seem to have at least one old phone sitting in a drawer that could be pressed into service as a temporary replacement as it takes about a week for an official replacement. If you've just got to have an iPhone, you can rent one from Apple for the duration.

But notebooks are a different matter, and the lighter they are, the more frequently they will be used in meeting rooms, conference halls, in cafes and on aircraft - all places where the demand for power points typically exceeds the supply, assuming any are provided. In these circumstances, a spare battery is a highly desirable accessory - you really don't want to worry about when you'll next be able to plug into the mains, or what you need to do to eke out the remaining charge.

As with the iPhone, the MacBook Air battery is permanently installed, and replacement takes about a week and costs $US129/$A199. We'll probably see aftermarket options fairly soon, starting with third-party replacement services and then battery kits including instructions and any necessary tools. As always, they're not for the dexterity challenged or faint hearted, and we'd think twice about a DIY job on a MacBook Air that was still covered by the original warranty or AppleCare.

Other manufacturers seem to be able to make remarkably slim devices without sacrificing easily replaceable batteries, but admittedly notebooks don't come any slimmer than the MacBook Air.