Cool mod. The replacement batteries aren't hard to come by where I live though. I can find them at my Wal-Mart. A buddy of mine actually replaced his original once, so I already knew of this.

Didja know that if you save the game three times while the batter is pretty much out and you can't save like normal, it will still save?  The first save does nothing, the second make a save file (corrupted), the third makes a complete save file.  Weird.  But true.  Maybe I should make a video of it in action?

Though, most likely because my battery had some juice left.

Sweet.  I have a Pokemon Blue that refuses to save, and an Emerald that loses the save data as soon as I take it out of the Gameboy.  (Although the Emerald is a Chinese hacked version.)