Amps vs. volts
I thought power was related to amps, not volts. Reading through the specs on various cordless drills, it seems that they come with battery packs at a number of different voltages: 7.2, 9.6, 12, 13.2, 14.4, 18, etc. The motors will be designed to work optimally at one particular voltageThe amount of power (amps) drawn by a particular drill from the battery packs seems to be selectable on some drills as a "torque" setting. Others don't appear to be adjustable in that manner.These "drills" also have accessories like spotlights & whatnot. They would run at the same voltage, but draw fewer amps.If you plug a 12V lightbulb into a 24V power supply, it'll quickly burn out. If you plug a 24V bulb into a 12V power supply, it'll just be dim. (I know that one, I've bought the wrong kind by mistake.) I'm presuming that the same would apply to drill motors???The link below is one I've been looking at:http://www.mytoolstore.com/milwauke/0502-20.htmlNote that you can buy a recharger that plugs into your car or boat cigarette lighter. I'd much rather wire the thing up directly. If possible.