The Nintendo DS Lite seems like it was made to have solar cells put on it. It has a large amount of surface area on the top and bottom that both face upward when the DS is opened. The top and bottom faces each have exactly the right amount of room for two 60x60mm solar cells side by side (four total). Each one has a maximum power output of 3 volts at 40 ma. The top two are connected in series and so are the bottom two. These two sets are wired in parallel to get a total of 6 volts at 80 ma, perfect for trickle-charging the battery.
My original instructable
had a couple of flaws, some of them very important. I was originally going to post the updates on my first instructable, but there were so many changes that I had to make a whole new one.
Among these changes are:
Overcharge protection (the main reason I wrote a new Instructable)
Only one wire connecting the top to the bottom, not two little annoying ones
No wires around the edges
No annoying diodes where your hand goes
You can get the stylus out now (I accidentally put a solar cell over it the first time, silly me)
Another thing I need to mention is why I didn't use a 5v regulator and hook it up to the charging jack of the DS. The reason I did not do that is because I would have to rewire the solar cells to produce a higher voltage for the voltage regulator. This would give me less than 40 ma. Running that through a voltage regulator reduces that even further. Also, the DS would have its charging LED on if I did this. That would suck about half of the remaining current, leaving next to nothing for the battery. If I did it that way, the battery would charge about 4 times slower.
This is my third Instructable, and if you have any questions, don't hesitate to post a comment! Don't forget to rate and vote either!