I came across a snag with my external camera flash when designing the Rotobooth (my flickr photobooth). The flash, a Canon 430ex, does not have a DC power option (the ability to plug into an external power source). This would require the four AA batteries to be swapped out approximately every 200 photos.As a work around, I cut a wooden dowel to size to make two false batteries to charge the capacitor. Voltage was easy to determine – 4 × 1.5 Volt batteries = 6VDC. Next I connected a bench power supply to watch the current draw (amperage). This determines how quickly the flash will charge.I have not used high current on these batteries yet, so you may need a regulator before running the leads (don\'t melt it into you battery compartment)! Thanks Corey.Also, I used screws on either side of the batteries to affix the leads and glued some copper mesh to maximize surface area of the conductors.