Just so you know, a 3Ah Ni-Cd battery is larger than most other battery packs for radio controlled cars. So they weigh more and are more expensive.

Concerning the speed controllers in the drills:
http://www.fightingrobots.co.uk/discus/messages/25/1201.htmlhttp://www.fightingrobots.co.uk/disc...s/25/1201.html