This is really interesting, but I'm having trouble with some of the numbers. Say the "two bars" consumption equals, roughly, 3 A-hr. At 20 volts, we have 60 W-hr. Just guessing here, but say you travelled that
6 miles at 12 mph.That means the drill was drawing an average of 120 W for a half-hour. Let's be generous and say that the system efficiency is 80% from storage to power at the drill shaft. So, given chain and friction losses at the tire, you have 1/8 hp driving the bike.
Will that be enough to move you at 12 mph? I'm not familiar with the actual power consumed by these bikes, but that sounds low. Am I missing something?