Review Sonnet isn't the only company to offer iPod battery upgrades, but it's the first to bundle a video installation guide. With printed instructions typically about as basic as it's possible to get, does Sonnet's approach make battery replacement an easier task for the non-techie?

Opening the blister pack exposes the slimline 3.7V battery, which Sonnet claims provides a 2200mAh capacity, though not on either the battery itself or the packaging it's sold in. The pack also contains a pair of plastic iPod disassembly tools, and a CD-ROM with the installation videos.

Sonnet provides movies in English, French, German and Japanese, with separate videos for first and second-generation iPods, third-generation players, fourth-generation devices, and the iPod Mini. You make your selection through a neat interactive, which finally fires up the appropriate video on QuickTime Player.

The movies are 320 x 240, which is a little small, I'd say, when viewed on any screen that's 1024 x 768 or larger. Fortunately, the picture quality is sufficiently good to allow you to drag the window out to near full-screen size and still see reasonably clearly what's going on.

After a warning against the perils of static electricity and a disclaimer freeing Sonnet from liability for damage you cause to your iPod, the video proceeds with the walkthrough. It's shot looking down on a black work space, so there's nothing to distract you from the procedure you'll follow. The voice-over is reassuring, and there are generally few edits so you're not left with the sense that Sonnet is glossing over the difficult bits. There are one or two instances where the demonstrator's hands get in the way, or a close-up would have been appropriate, but generally the narration and pictures make it clear what you have to do.

Having watched the video through to familiarise myself with what I was about to do, I set to work replacing the battery in my first-generation iPod, which I've owned and used for almost four years. To check the benefits of the upgrade, I charged my unmodified iPod overnight and then played through the 972 songs in sequence, over and over until the battery drained. I connected the standard-issue earphones and set the volume to 50 per cent.

I got around nine hours and 37 minutes of playtime out of it, though that's more than I feel I get when I'm out and about, not least because of the way power seems to leach out of it while it's sitting on the shelf, and because I change tracks more frequently, activating the hard drive every time.

Swapping in the new battery proved relatively straightforward. It's not quite as easy as the video makes it appear - separating the battery and the hard drive took rather more force than it seems to take the guy on the screen, for example. But it's certainly easier to grasp what to do next and how to do it from a video than it is from a series of static drawings.

Sonnet recommends iPod Mini and fourth-generation iPod users seek professional installation expertise rather than upgrade themselves. Since you need to go at the thing with a hair dryer to loosen the metal casing and weaken adhesive, it's not hard to see why. But if you're brave enough, the video will at least take you gently by the hand through the entire replacement process. It's clear from the videos that patience is more of a virtue than technical ability, and if you take your time, pausing the video as you go, you shouldn't run into difficulty.

I recharged the Sonnet battery fully and re-ran the play duration test. Sonnet claims the new cell should provide up to 78 per cent more runtime than the original battery, based on the two power sources' respective storage capacities. I got more than 22 hours and 15 minutes out the Sonnet battery.

Verdict

If you have an older iPod and you're getting seriously miffed that it's not lasting as long as it used to, $40 is a very small price to pay to revive it - and then some. I more than doubled my player's run-time, for a fraction of the cost of the comparable-capacity iPod Nano I'd been considering as a replacement.

With the exception of the iPod Mini and the fourth-generation iPod, both of which need careful heating to loosen adhesive, the replacement process is straightforward, and Sonnet's videos make it as easy to undertake as any form of instruction can. With the other models, you still need to take care, but you definitely don't need to be an expert.

This is one of the best upgrade packages I've seen, doubly so since it's pitched at a device Apple never intended to be upgradeable. I'd recommend it to all owners of older iPods. ®