I use cyclone Kits my best is the 36v 100w for the mountain we live on, but most i make up are 500w 24v & use the 3 chainwheel kit but make up my own crank using cyclone crank that fits the freewheel,their's the chain gets stuck in between -----The -Only battery is LiFePo4 buy the cells & Bms easy (from BMS china-you'll jhave to google it )to make up but make my own pack that will fit any mountain bike(stuffed a whole BMS once though), My next experiment is nu-vinci hub wish to here more on these with 500w or more motors.