There are many possible types of electric bikes with several technologies available for electric motors, varying in cost and design.  The direct-drive and geared motor units are both used. An electric power-assist system may be added to almost any pedal cycle. Chain drive and hub motors are both common, friction drive less so. Most hub motors are in the 250w to 450w category, however there are some available with up to 2000 watts such as Crystalyte Phoenix.

Electric bicycles are generally powered by rechargeable batteries. These are normally charged from the utility supply (mains), with perhaps the option of using the motor to effect regenerative braking or charging while being pedalled or rolling downhill. There are also experiments with recharging via solar panels and, to a lesser extent, other alternative energy sources such as fuel cells. Most modern electric bikes use technologies such as rare earth magnets, pulse width modulated power electronic control and regenerative braking to improve efficiency. Batteries are usually either lead-acid, NiCd, NiMH or Li-ion. Lithium ion polymer batteries are now beginning to be used as well, offering the advantage of lighter weight for the same energy storage capability but at a higher cost.

An electric motorized bike can be power-on-demand, where the motor is activated by a handlebar mounted throttle, and/or a pedelec (from pedal electric), where the electric motor is regulated by pedaling. These may have a mechanism such as a crank sensor to detect when the user is pedaling, or a more sophisticated torque sensor. The degree of assistance can usually be controlled to optimize battery life.

Range is a key consideration with electric bikes, and is affected by factors such as motor efficiency, battery capacity, efficiency of the driving electronics, aerodynamics, hills and weight of the bike and rider combined. The range of an electric bike is usually stated as somewhere between 7km (uphill on electric power only) to 70km (minimum assistance).