Everyone at some point has been frustrated at their battery running out, cursing for not charging it the night before, and wishing that the iPod like mp3 players of old would come with replaceable batteries. Well, here is a product that is almost what you wish for. The Belkin iPod Extended Battery is a plug-in device containing 4 AA batteries that can be used to charge up your iPod whilst on the move.

This play-time extender from Belkin consists of a plastic case to hold the batteries and a short cable to insert into the dock connector. It also has 2 suction cups to attach it to the metal back of the iPod, an LED indicator of power levels, and a secure switch to prevent accidental switching on and off.

The Belkin iPod Extended Battery aims to provide up to 20 hours of extended play on a set of four AA batteries (and a full internal iPod battery). It does this reasonably well, depending on the state of your iPod battery, and is definitely a good emergency backup should you be caught miles from the nearest plug socket. An advantage of having to use replaceable batteries (though you could always use rechargeable ones) is that the power-supplying ability of the device is not going to diminish, whereas if it the battery pack itself has to be charged you may lose power over time. The potential for listening to your music is essentially limitless, provided you have enough batteries, and it is great for when you forget to charge your iPod.

However, for all its functionality, it isn’t the most stylish of accessories. It is bulky and unattractive, and although it aims to complement the iPod in style, its size and weight doubles that of the iPod in both respects. It is definitely a good concept, and useful if you don’t need to carry your iPod around independently, such as if you were on a plane or had a bag to put it in. It would not look cool attached to a belt clip, and definitely would not fit in any normal sized pockets. The suction cups do provide a sturdy, scratch-free attachment to the iPod, but would be useless if the iPod was in a case (except an iSkin or Speck Skin which are made of rubber). Also, if used when doing physical activity the cups wouldn’t be that secure, but unless you are doing a marathon you shouldn’t need that much battery power.

In summary, the Belkin iPod Extended Battery does what it sets out to accomplish, but it doesn’t do it with particular grace. It adds little-needed weight and bulk to a meant-to-be-portable device. A little re-engineering and a different type of battery could solve some problems, but that is for Belkin to accomplish.