An electric bicycle is a motorized bicycle with an integrated electric motor used to assist propulsion. Many kinds of e-bikes are available worldwide, but they generally fall into two broad categories: bikes that assist the rider's pedal-power and bikes that add a throttle, integrating moped-style functionality. Both retain the ability to be pedaled by the rider and are therefore not electric motorcycles. E-bikes use rechargeable batteries and typically are motor-powered up to 25 to 32 km/h . High-powered varieties can often travel more than 45 km/h .