Picture yourself ambling down a country road with your newly minted monster to terrorize a village when suddenly he conks out. Now what?
This picture suggests so. This article suggests that giving yourself a boost, even a very small one from a 9V battery can even make you a better shot, eliminating the need to get up in the villagers faces.
A Google search on "9V brain stimulation" yields a plethora of information including detailed instructions on how to build the simulators for well under $10. Of course you could buy one already built but prices go as high as $600. Keep this in mind if you're out of work and looking to raise a few bucks.