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The Electric Vehicle Guide

Basics | Benefits | Recharging | Bikes | Scooters | Cars & Vans

EV bikes

Electric-assist bicycles (and tricycles) use a battery-motor system to provide additional power when required (to increase speed or assist uphill). Models are either based on standard bicycles, or are dedicated designs that fully integrate the electric propulsion systems within the frame. Retrofit devices are also available that can be used to provide standard bicycles with electric assist. Electric power is either activated by a handlebar-mounted throttle, or by use of the pedals ('pedelec' from pedal electric).

The key aspects of the design of an electric-assist bicycle are its weight, and its choice of frame, battery, motor and controller. Although lighter bikes generally have better performance, a lightweight frame can reduce flexibility and strength. While conventional lead-acid batteries are able to provide adequate range, newer battery types (including Ni-MH, Li-Ion and Li-Poly) significantly improve range. Drive train options inlcude direct-drive, chain-drive, hub motors and wheel-mounted friction drive.

Most EV bikes will come supplied with an off-board charger specifically designed to recharge the type of battery used in such a way to maximise battery life. Recharging times depend on several factors including battery capacity and battery type with typical recharge times ranging from 2-6 hours. Vehicle range on a full charge also depends on the battery used and can vary from 5 miles (uphill using electric power only) to 50 miles (human power with minimum electric assistance).

Purchase costs for electric assist bikes (of all types) are higher than their conventional equivalents due to the addition of the battery and motor. Battery replacement costs are also incurred as most units need to be replaced every 3-5 years. On the plus side, fuel costs are very low due to the high efficiency of the vehicles themselves and the fact that electricity is effectively (fuel) tax free. Typically for an electric-assist bike, battery recharge costs are 2-5p and fuel costs are around 0.5p/mile.

Under current UK regulations, an electric-assist bike can be ridden by anyone aged 14 or over, and does not require a licence, third-party insurance, road tax or registration plates provided: it weighs 40kg or less (60kg tandems/tricycles); it is fitted with pedals by which it can be propelled; it has a motor of no more than 200W continuous output (250W tandems/tricycles); the motor does not propel the vehicle when it is travelling faster than 25km/h (15.5mph); and power to the motor is cut automatically when the brakes are applied.

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• Recharging
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• Electric scooters