I got an inexpensive variable buck converter power supply on Banggood.com. http://www.banggood.com/DC-DC-Step-Down-Power-Supply-Adjustable-Module-With-LCD-Display-Without-Housing-Case-p-1038737.html
I needed a good DC power source for the input and thought about my 18v Black and Decker battery. Inspiration came from the ‘Cordless Drill Battery Pack Adapter Plug’ ( http://www.thingiverse.com/thing:45159 ) which I made some time ago. Although this is a scratch made model.
I know this project does not have universal appeal since every brand of cordless battery is different but I hope it will inspire you to make an adaptor for your brand.
Printed on a Printrbot Play using Hatchbox PLA.
Printed vertically. No support or brim (My printer does a good job of bridging… your results may be different.)
Layer height: .02064
Shell thickness: .8
Fill Density: 10%
Print speed: 50 mm/s
Hot End Temp: 208c