Cyclemotor Drivetrain

P.O. Box 55252
Madison, WI 53705

The Cyclemotor is driven by a powerful (1 Horsepower) direct drive hub motor. This motor is very quiet, emitting only a slight whirring sound at the highest power levels.

Note the unusual spoke pattern above, which we call half-cross. Motor was disassembled to determine if hub wall was thick enough to withstand torsion stress from the half-cross spoke pattern. It was, so we used this pattern instead of radial spokes. This resulted in a stronger wheel.

Coils inside the hub motor are affixed to the axle, and neodymium magnets are attached to the inside of the hub housing. Current to the motor coils is switched by transistors in the motor controller. This is a very durable motor because it lacks gears and brushes.


The prototype Cyclemotor uses Lithium-Iron Phosphate battery packs manufactured by Dewalt. The cells in these packs were produced by A123 Systems. These packs were chosen to demonstrate what is possible with existing technology. We did not modify the packs or chargers, so that we could take advantage of the control electronics built into the packs. Packs are switched on with external optical relays. A detailed description and schematic of the pack switching circuitry is available in the PDF file linked to below.

Battery Switch Schematic (PDF)

Four packs are wired in a series-parallel format. This becomes a 72 Volt, 4.4 AHr power pack. It will drive the Cyclemotor 10-20 miles between charges. Charging time is only one hour. Cycle life is over 2000, with full discharge and fast recharge. Assuming 15 miles per charge, this means that these batteries can be driven over 30,000 miles before replacement.