A few months ago I did the mod that has you drill out the reflector in a mini Mag, and you can use the bulb out of a 2D light instead. While this did about double the brightness, I was thinking about using two lithium cells and a 6D bulb, since they would give 8.4v at a fresh charge, below the limit of the 9v bulb. I'm very new to this, and I thought it would be a bit of fun, but I know lithium batteries are dangerous. Assuming I use protected cells, so I need to worry about anything? I'm really not trying to create a small explosive device, so if I'm doing anything stupid please let me know.