I did this two years ago when I was about to leave for Greece. It was on my previous blog and I just decided to import it here. Go:
The context, in brief.
I always listen to music, but it's almost always on a computer. Well, yes, I am one of those young geeks who couldn't live without a computer for more than two weeks. Since I am leaving for a more than two weeks in a remote place, I bought an iPod nano to avoid death. "Yes it is recharged by the USB... so what?" Having a computer nearby is so natural, I haven't though I won't be able to charge it while I will be away.
The solution, in brief.
Give that picky pod its 5V on a female USB from a power source that would be available everywhere around the world (or almost); a battery with enough mAh to resurect the dead pod. A kind of portable USB charger for iPod nano.
The engineering, in brief.
The resurection solution is so simple, it's almost a pod defibrilation. A pack of batteries, a LM7805 I stol from an old university project, and imagination. I chose a sardine metal box to put the stuff in it. It was the perfect size for extra batteries, heat sink and female connector. The most difficult part was to eat the sardines. Some photos can be seen in the "ipod nano recharger" album. Here is the schematic:
I should have put a diode to avoid to sink the guts of an alive pod to a dead 9V battery.
Do:
1) Use that only in case of absolute necessity.
2) Secure your wires in glue; solder points are weak if you don't use a printed circuit board.
3) Make sure the LM7805 can dissipate its heat and stay cool.
4) Try to find a better metal box than sardines ;)
Do not:
1) Never plug in an alive pod, wait until it is dead.
2) Don't plug in your pod if you have not verified all the voltage and current levels; put some resistors to simulate the pod's load.
Here are some pictures:





It's good to have extra batteries, but make sure the battery terminals won't touch the metal casing, this will cause a battery sink. The inside of the sardine box is plastified so it's ok. Test the surface with your ohmmeter.