I'm thinking about some 18v drills but a dual battery set up might be a good idea, the 30 amp electronize i'm using for the axe is 24v max and a 6s lipo fully charged is around 25ish, i know that No Toy runs that set up but his axe runs on a bigger ratio with smaller gear motors so maybe it's easier on the ESC that way, besides the way that Hatchet's axe ran on the current ratio on just 16.8v Nimh proves that it has the power already so if i increase the ratio slightly and up the voltage to 5s i reckon it'll have more than enough power without being over the top.