Electric bikes and E-bike kits (bikes with electric conversion kits) are part of a wide range of Light Electric Vehicles (LEVs) that provide convenient local transportation. Generally designed for one person and small cargo capacity, electric bike range, speed, and cost are moderate. For most of us, the majority of our trips are less than 20 miles - within the range of most e-bikes considering the latest advances in affordable lithium batteries. Clean, quiet, and efficient LEVs offer the advantages of an extra car without the burdens.
A 2008 market survey showed that the average distance traveled in the Netherlands by commuters on a standard bicycle is 6.3 kilometres (3.9 mi) while with an e-bike this distance increases to 9.8 kilometres (6.1 mi). This survey also showed that e-bike ownership is particularly popular among people aged 65 and over, but limited among commuters. The e-bike is used in particular for recreational bicycle trips, shopping and errands.
All Kalkhoff bikes come with lots of extras: hub or motor powered front and rear lights, bells, fenders, chain guards and racks. Some include a built-in quick-lock or a rack-mounted pump. There are a number of features available for the discerning cyclist, whether it's the Magura hydraulic brakes, the B&M super-bright hub-powered headlight, the top-of-the-line Shimano internal hub or derailleurs or the three-layer powder-coated paint process.
Unlike most e-bikes, the Brompton's battery is integrated into a bag that sits on the front of the bike. While that detracts slightly from the classic, streamlined design, it's handy as it can be unclipped for charging or riding as a regular bike – it's probably one of the easiest to ride without battery assistance thanks to its weight. The battery also powers two lights for safe commuting.
Controllers for brushless motors: E-bikes require high initial torque and therefore models that use brushless motors typically have Hall sensor commutation for speed and angle measurement. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. The controllers generally allow input by means of potentiometer or Hall Effect twist grip (or thumb-operated lever throttle), closed-loop speed control for precise speed regulation, protection logic for over-voltage, over-current and thermal protection. Bikes with a pedal assist function typically have a disc on the crank shaft featuring a ring of magnets coupled with a Hall sensor giving rise to a series of pulses, the frequency of which is proportional to pedaling speed. The controller uses pulse width modulation to regulate the power to the motor. Sometimes support is provided for regenerative braking but infrequent braking and the low mass of bicycles limits recovered energy. An implementation is described in an application note for a 200 W, 24 V Brushless DC (BLDC) motor.
For many bikes, battery range is more important that total power (because they're all pretty powerful). You want a bike that delivers a range long enough for your rides at the power levels you want. Most e-bikes will have three to five levels of assist kicking in anywhere from 25 percent of you pedal power to 200 percent boost. Consider how fast the battery takes to recharge, especially if you'll be using your bike for long commutes.