I had an old junker bike that the guys at the bike shop gave me. It was pretty rough but had all the parts just needed a new chain.
This was enough to test the motor out with just 2 6S 5 amp/hour batteries in series for power. I've since made a bracket to mount the controller under the frame and I think I can get 15 amp hour 12S worth of batteries in the space in front of the rear shock.