Its quite simple whats becoming popular here is using 18 volt drill batterys and simply making a plug to insert into the the batterys plug insert and thats it. This works very well. I run my three units, a halfA starter and two cheapie units at 16.8 volts. Do this anyd you will never go back to ordinary 12 volt arraingements. The starters can be just plain old cheapies (they work well at the higher voltages).

Remember with starters voltage is king you want to improve performance you increase the voltage, its as simple as that.

I would never suggest using a pistol grip drill for a starter however as they will become quite dangerous when used one handed (and most people do revert to this) with the totally wrong trigger orientation.