I bought a first generation iPod Nano more than 2 years ago. I use it every work day (see also https://dbenn.wordpress.com/2006/08/27/astronomy-science-podcasts/), but the battery has been on the way out over the last few months. In the end it was holding charge for less than an hour, irrespective of charge time, often dying before my walking trip was over.
Getting it replaced through official channels would’ve cost in excess of AUD $100, about a 3rd of the device’s original cost. So instead, I spent AUD $20 on an iPod replacement battery kit from JayCar (I’ve seen them advertised elsewhere on the web too).
It came with the 3.7V Li-ion Polymer battery (400mAh instead of the original 340mAh), two plastic tools to pry the case open, and a brief but effective instruction sheet.
The most painful part was getting the case open. The plastic tools from the kit only get you so far and I pretty much wrecked mine. My wife Karen and I took turns carefully prying open different sections of the case with a small flat blade jeweller’s screwdriver (not suggested by the instruction sheet, but effective nonetheless), in addition to using the plastic tools.
Once the back of the case was off, the battery was easily removed, and I used a fine-tipped soldering iron to remove the three wires from the PCB, and fine solder to connect the new battery’s wires in place before putting the case back together.
I replaced the battery on the weekend and didn’t have to charge it again until 3 days later. Hopefully this will make my Nano last another 2 or 3 years, by which time it will probably be time for an iPod upgrade. It won’t owe me anything by then, that’s for sure.
Now, all I have to do is stop breaking earphones.