I'd pretty much been planning on an Etek-RT with Kelly controller with regen, and lo and behold, found that Phil Thayer had done a nice clean Ninja 250 conversion with this combo:

[Link]

His performance and range numbers on 30 Ah batteries I found encouraging. I'd like a peak speed a little higher than 50, as my primary riding will be on roads with 30 to 45 mph speed limits, and it's always good to have some throttle move to get out of the way when...