I go camping for extended periods of time in places with no electricity, and I had checked out getting the Belkin Battery Pack for my iPod, so I could always pack extra batteries and rock it out for a week or more away from civilization, but the price turned me off quickly.
Belkin charges close to $70 for these pieces of plastic! All it is, is 4 AA batteries in series, connected to a short version of the Apple iPod Dock Connector.
I said to myself (and probably a few other people); Hell, I can do that myself cheaper and with less batteries.
A little planning and ordering of a handful of parts, I set to work to create my own version of the iPod Battery Pack.
All the parts in this project I got from Radio Shack, except for the Altoids tin, which you can find at any drugstore, and the firewire socket, which can be had for $1.93 each from HERE
I can't claim to be the first to do it though, Drew Perry drew up a short article on how he made his HERE, which I borrowed the schematic for since two 9volts and 2 AA batteries should last much longer than 8AA batteries, and in a pinch, it could be run off of a single 9volt.
Here's his diagram:
The power lead connects to pin 1 on the firewire socket, and pin 2 is the ground.
Edit: Since this articles inception, I have recieved far too many emails where people are confused by even this simple diagram, so I took a few minutes to whip this up. I hope is cuts down on the confusion.
The tolerance for the hole I filed out for the firewire jack is pretty exact, and I soldered the jack to the case all around the edges. You won't have to worry about breaking it. I also have soldered all connections to the firewire, and coated it with hot glue for safety and durablility.
Here is a picture of my finished unit charging my 3rd generation iPod with the Apple supplied cable. Since the 1st and 2nd generation ipods also run off of 12volts firewire, they can also be used with the battery pack with any standard firewire cable.
and NO, I don't know if it will work with 4th Gen models or the Mini.