A laser taking 3 amps?
What the hell kind of laser did you get? Are you trying to build a laser-saw? 3 amps is nuts... I've played with a few lasers... a pistol mounted laser only puts out from 60ma to 100ma.. and those are fairly strong.
Yeah Ty.. geeze! All this negativity.. 
Have you thought about making it wireless? Plug it into a wall outlet and control it via RF link and put it in your lawn, lol, and time how long it takes for the police to arrive. 