a word of warning to anyone thinking of buying a cyclone 650 watt kit and planning on running it on 24 volt dont just buy the 500 watt kit with built in speed controller .i run my cyclone kit with a high power nimh 36 volt battery now and it goes well around 33 or 34 mph on level ground with no pedaling with the 24 volt it would only do 23 mph the same as my 500 watt kit i love the way the motor now revs allot more with the extra volts this means less gear changing .so far the speed controller has been fine at 36 volts