I have an external flash for my DSLR camera (a Canon Speedlite 430 EX II) that runs on 4 AA batteries. I plan on using this flash in a photo booth at a wedding, so it would be great if I could hack some sort of external power supply for this flash, instead of having to replace batteries several times during the day.
I saw several website describing ways of building "fake batteries" that allow to connect an external battery or power supply to cameras or flashes (for example, http://blog.davidburren.com/2003/03/flash-power-pack.html).
Would there be any danger/downside to building a fake battery pack that connects to an external 6V power adapter (for example a 6V 2A AC / DC power adapter)? How would you do it?