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An electric bicycle, also known as an e-bike, is a bicycle with an integrated electric motor which can be used for propulsion. There are a great variety of different types of e-bikes available worldwide, from e-bikes that only have a small motor to assist the rider's pedal-power (i.e. pedelecs) to somewhat more powerful e-bikes which tend closer to moped-style functionality: all however retain the ability to be pedalled by the rider and are therefore not electric motorcycles. E-bikes use rechargeable batteries and the lighter varieties can travel up to 25 to 32 km/h (16 to 20 mph), depending on the laws of the country in which they are sold, while the more high-powered varieties can often do in excess of 45 km/h (28 mph). In some markets, such as Germany, they are gaining in popularity and taking some market share away from conventional bicycles, while in others, such as China, they are replacing fossil fuel-powered mopeds and small motorcycles.
Depending on local laws, many e-bikes (e.g. pedelecs) are legally classified as bicycles rather than mopeds or motorcycles, so they are not subject to the more stringent laws regarding their certification and operation, unlike the more powerful two-wheelers which are often classed as electric motorcycles. E-bikes can also be defined separately and treated as a specific vehicle type in many areas of legal jurisdiction.
In the 1890s, electric bicycles were documented within various U.S. patents. For example, on 31 December 1895, Ogden Bolton Jr. was granted U.S. Patent 552,271 for a battery-powered bicycle with “6-pole brush-and-commutator direct current (DC) hub motor mounted in the rear wheel.” There were no gears and the motor could draw up to 100 amperes (A) from a 10-volt battery.
Two years later, in 1897, Hosea W. Libbey of Boston invented an electric bicycle (U.S. Patent 596,272) that was propelled by a “double electric motor.” The motor was designed within the hub of the crankset axle. This model was later re-invented and imitated in the late 1990s by Giant Lafree e-bikes.
By 1898 a rear wheel drive electric bicycle, which used a driving belt along the outside edge of the wheel was patented by Mathew J. Steffens. Also, the 1899 U.S. Patent 627,066 by John Schnepf depicted a rear wheel friction “roller-wheel” style drive electric bicycle. Schnepf's invention was later re-examined and expanded in 1969 by G.A. Wood Jr. with his U.S. Patent 3,431,994. Wood’s device used 4 fractional horsepower motors; connected through a series of gears.
Torque sensors and power controls were developed in the late 1990s. For example, Takada Yutky of Japan filed a patent in 1997 for such a device. In 1992 Vector Services Limited offered and sold an e-bike dubbed Zike. The bicycle included Nickel-cadmium batteries that were built into a frame member and included an 850 g permanent-magnet motor. Despite the Zike, in 1992 hardly any commercial e-bikes were available.
Production grew from 1993 to 2004 by an estimated 35%. By contrast, according to Gardner, in 1995 regular bicycle production decreased from its peak 107 million units.
Some of the less expensive e-bikes used bulky lead acid batteries, whereas newer models generally used NiMH, NiCd and/or Li-ion batteries which offered lighter, denser capacity batteries. Performance varied; however, in general there was an increase in range and speed.
By 2001 the terms e-bike, power bike, "pedelec", pedal-assisted, and power-assisted bicycle were commonly used to refer to e-bikes. The terms "electric motorbike" or "e-motorbike" refer to more powerful models that attain up to 80 km/h (50 mph).
In a parallel hybrid motorized bicycle, such as the aforementioned 1897 invention by Hosea W. Libbey, human and motor inputs are mechanically coupled either in the bottom bracket, the rear or the front wheel, whereas in a (mechanical) series hybrid cycle, the human and motor inputs are coupled through differential gearing. In an (electronic) series hybrid cycle, human power is converted into electricity and is fed directly into the motor and mostly additional electricity is supplied from a battery.
By 2007, e-bikes were thought to make up 10 to 20 percent of all two-wheeled vehicles on the streets of many major cities. A typical unit requires 8 hours to charge the battery, which provides the range of 25 to 30 miles (40 to 48 km), at the speed of around 20 km/h.
E-bikes are classed according to the power that their electric motor can deliver and the control system, i.e. when and how the power from the motor is applied. Also the classification of e-bikes is complicated as much of the definition is due to legal reasons of what constitutes a bicycle and what constitutes a moped or motorcycle: as such the classification of these e-bikes varies greatly across countries and local jurisdictions.
Despite these legal complications, the classification of e-bikes is mainly decided by whether the e-bike's motor assists the rider using a pedal-assist system or by a power-on-demand one. Definitions of these are as follows:
Therefore, very broadly, e-bikes can be classed as:
E-bikes with pedal-assist only are usually called pedelecs but can be broadly classified into pedelecs proper and the more powerful S-Pedelecs.
The term "pedelec" (from pedal electric cycle) refers to an e-bike where the pedal-assist electric drive system is limited to a decent but not excessive top speed, and where its motor is relatively low-powered. Pedelecs are legally classed as bicycles rather than low-powered motorcycles or mopeds.
The most influential definition which distinguishes which e-bikes are pedelecs and which are not, comes from the EU. From the EU directive (EN15194 standard) for motor vehicles, a bicycle is considered a pedelec if:
An e-bike conforming to these conditions is considered to be a pedelec in the EU and is legally classed as a bicycle. The EN15194 standard is valid across the whole of the EU and has also been adopted by some non-EU European nations and also some jurisdictions outside of Europe (such as the state of Victoria in Australia).
Pedelecs are much like conventional bicycles in use and function — the electric motor only provides assistance, most notably when the rider would otherwise struggle against a headwind or be going uphill. Pedelecs are therefore especially useful for people living in hilly areas where riding a bike would prove too strenuous for many to consider taking up cycling as a daily means of transport. They are also useful when it would be helpful for the riders who more generally need some assistance, e.g. for elderly people.
More powerful pedelecs which are not legally classed as bicycles are dubbed S-Pedelecs (short for Schnell-Pedelecs, i.e. Speedy-Pedelecs) in Germany. These have a motor more powerful than 250 watts and less limited, or unlimited, pedal-assist, i.e. the motor does not stop assisting the rider once 25 km/h has been reached. S-Pedelec class e-bikes are therefore usually classified as mopeds or motorcycles rather than as bicycles and therefore may (depending on the jurisdiction) need to be registered and insured, the rider may need some sort of driver's license (either car or motorcycle) and motorcycle helmets may have to be worn.
Some e-bikes have an electric motor that operates on a power-on-demand basis only. In this case, the electric motor is engaged and operated manually using a throttle, which is usually on the handgrip just like the ones on a motorbike or scooter. These sorts of e-bikes often, but not always, have more powerful motors than pedelecs do.
With power-on-demand only e-bikes the rider can:
Please note that some power-on-demand only e-bikes can hardly be confused with, let alone categorised as, bicycles. For example, the Noped is a term used by the Ministry of Transportation of Ontario for e-bikes which do not have pedals or in which the pedals have been removed from their motorised bicycle. These are better categorised as electric mopeds or electric motorcycles.
|This section needs additional citations for verification. (June 2010)|
In Australia the e-bike is defined by the Australian Vehicle Standards as a bicycle that has an auxiliary motor with a maximum power output not exceeding 200 W without consideration for speed limits or pedal sensors. Each state is responsible for deciding how to treat such a vehicle and currently all states agree that such a vehicle does not require licensing or registration. Various groups are lobbying for an increase in this low limit to encourage more widespread use of e-bikes to assist in mobility, health benefits and to reduce congestion, pollution and road danger. Some states have their own rules such as no riding under electric power on bike paths and through built up areas so riders should view the state laws regarding their use. There is no licence and no registration required for e-bike usage.
Since 30 May 2012, Australia has an additional new e-bike category using the European Union model of a pedelec as per the CE EN15194 standard. This means the e-bike can have a motor of 250W of continuous rated power which can only be activated by pedalling (if above 6 km/h) and must cut out over 25 km/h - if so it is classed as a normal bicycle. The state of Victoria is the first to amend their local road rules to accommodate this new standard which came into effect on the 18th of September 2012.
Eight provinces of Canada allow electric power assisted bicycles. In seven of the eight provinces, e-bikes are limited to 500 W output, and cannot travel faster than 32 km/h (20 mph) on motor power alone on level ground. In Alberta, the limits are 750 W and 35 km/h (22 mph). Age restrictions vary in Canada. All require an approved helmet. Regulations may or may not require an interlock to prevent use of power when the rider is not pedaling. Some versions (e.g., if capable of operating without pedaling) of e-bikes require drivers' licenses in some provinces and have age restrictions. Vehicle licenses and liability insurance are not required. Generally, they are considered vehicles (like motorcycles and pedal cycles), so are subject to the same rules of the road as regular bicycles. In some cases, regulatory requirements have been complicated by lobbying in respect of the Segway PT.
Bicycles assisted by a gasoline motor or other fuel are regulated differently than e-bikes. These are classified as motorcycles, regardless of the power output of the motor and maximum attainable speed.
Note that in Canada, the term "assist bicycle" is the technical term for an e-bike and "power-assisted bicycle" is used in the Canadian Federal Legislation, but is carefully defined to only apply to electric motor assist, and specifically excludes internal combustion engines (though this is not the case in the United States).
In China, e-bikes currently come under the same classification as bicycles and hence don't require a driver's license to operate. Previously it was required that users registered their bike in order to be recovered if stolen, although this has recently been abolished. Due to a recent rise in electric-bicycle-related accidents, caused mostly by inexperienced riders who ride on the wrong side of the road, run red lights, don't use headlights at night etc., the Chinese government plans to change the legal status of illegal bicycles so that vehicles with an unladen weight of 20 kg (44 lb) or more and a top speed of 30 km/h (19 mph) or more will require a motorcycle license to operate, while vehicles lighter than 20 kg (44 lb) and slower than 30 km/h can be ridden unlicensed. In the southern Chinese cities of Guangzhou, Dongguan and Shenzhen, e-bikes, like all motorcycles, are banned from certain downtown districts. There are also bans in place in small areas of Shanghai, Hangzhou and Beijing. Bans of "Scooter-Style Electric Bikes" (SSEB) were however cancelled and in Shenzhen e-bikes may be seen on the streets nowadays (2010–11).
European Union directive 2002/24/EC exempts vehicles with the following definition from type approval: "Cycles with pedal assistance which are equipped with an auxiliary electric motor having a maximum continuous rated power of 0.25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25 km/h (16 mph) or if the cyclist stops pedaling.” This is the de facto definition of an electrically assisted pedal cycle in the EU. As with all EU directives, individual member countries of the EU are left to implement the requirements in national legislation.
European product safety standard EN 15194 was published in 2009. The aim of EN 15194 is "to provide a standard for the assessment of electrically powered cycles of a type which are excluded from type approval by Directive 2002/24/EC".
In Israel, persons above 14 years old are allowed to use pedal-assisted bicycle with power of up to 250W and speed limit of 25 km/hour. The bicycle must satisfy the European Standard EN15914 and be approved by the Standards Institution of Israel. No license or insurance is required. Other motorized bicycles are considered to be motorcycles and should be licensed and insure as such. The maximum weight of the e-bike itself cannot exceed 30 kg.
In New Zealand, the regulations read: "AB (Power-assisted pedal cycle) A pedal cycle to which is attached one or more auxiliary propulsion motors having a combined maximum power output not exceeding 300 watts." This is explained by NZTA as "A power-assisted cycle is a cycle that has a motor of up to 300 watts. The law treats these as ordinary cycles rather than motorcycles. This means that it is not necessary to register or license them. Note that the phrase "maximum power output" that is found in the regulation (but omitted in the explanation) may create confusion because some e-bike motor manufacturers advertise and print on the motor their "maximum input power" because that number is larger (typically motors run at about 80% efficiency ) thus give the impression the buyer is getting a more powerful motor. This can cause misunderstandings with law enforcement officers who do not necessarily understand the difference, and when stopping a rider on an e-bike in a traffic stop, look at the number on the motor to determine if the e-bike is legal or not.
In Norway, e-bikes are classified as ordinary bicycles, according to the Vehicle Regulation (kjøretøyforskriften) § 4-1, 5g. Hence, e-bikes are not registered in the Vehicle Registry, and there is no demand for a license to drive them. Still, there are constraints on the bicycle construction. The maximum nominal motor power output can be no more than 250 watts and the maximum performance speed of the vehicle when the engine is running is 25 km per hour (15 mph). A function that reduces motor power when vehicle speed exceeds 25 km per hour is mandatory. However, if the motor is not running, the e-bike, or any other bike, answer only to the constraints of the ordinary speed limits.
In the United Kingdom, e-bikes are classed as standard bicycles providing the motor's maximum continuous rated power output does not exceed 200 W for bicycles, 250W for bicycle tandems (i.e. two seaters) and 250W for tricycles, and cuts out once the bike reaches 15.5 mph (24.9 km/h). It must also be under 40 kg (88 lb) for a bicycle, or 60 kg for a tricycle.
Riders must be at least 14 years of age, but no driving licence is required.
Federal law in the United States states that an e-bike must have a top speed when powered solely by the motor under 20 mph (32 km/h) and a motor which produces less than 750 W (1.01 hp). They are not considered motor vehicles by the federal government and are subject to the same consumer safety laws as unassisted bicycles. Their legality on public roads is under state jurisdiction, and varies. See the main Electric bicycle laws article for details on the law in individual states.
E-bike usage worldwide has experienced rapid growth since 1998. It is estimated that there were roughly 120 million e-bikes in China as of early 2010, and sales are expanding rapidly in India, the United States of America, the Netherlands, and Switzerland. A total of 700,000 e-bikes were sold in Europe in 2010, up from 200,000 in 2007 and 500,000 units in 2009.
Today, China is the world's leading producer of e-bikes. According to the data of the China Bicycle Association, a government-chartered industry group, in 2004 China's manufacturers sold 7.5 million e-bikes nationwide, which was almost twice the year 2003 sales; domestic sales reached 10 million in 2005, and 16 to 18 million in 2006.
PikeResearch, a for-profit market research firm, released a report in 2010 which included market analysis and forecasts for electric two-wheel vehicles. They conclude that, "The worldwide electric two-wheel vehicle market is expected to grow at a compound annual rate of 9% through 2016" and that "a lack of a well-defined retail channel hampers faster adoption in North America and Europe." PikeResearch also forecasted that worldwide sales of e-bikes, e-motorcycles, and e-scooters will reach more than 466 million between 2010 to 2016, and China will continue to dominate the world market, with more than 95% of sales during this period. E-bikes sales are expected to have the largest share with 56% of the market.
However, the Los Angeles Times reported that e-bike sales in the U.S. have slowed in 2010 compared to 2009. This could be due to a slowing economy."
There are many possible types of electric motorized bicycles with several technologies available, varying in cost and complexity; direct-drive and geared motor units are both used. An electric power-assist system may be added to almost any pedal cycle using chain drive, belt drive, hub motors or friction drive. BLDC hub motors are a common modern design with the motor built into the wheel hub itself and the stator fixed solidly to the axle and the magnets attached to and rotating with the wheel. The bicycle wheel hub is the motor. The power levels of motors used are influenced by available legal categories and are often, but not always limited to under 750 watts.
E-bikes use rechargeable batteries, electric motors and some form of control. Battery systems in use include sealed lead-acid (SLA), nickel-cadmium (NiCad), nickel-metal hydride (NiMH), llithium-ion polymer (Li-ion), and lithium-iron phosphate (LiFePO4). Batteries vary according to the voltage, total charge capacity (amp hours), weight, the number of charging cycles before performance degrades, and ability to handle over-voltage charging conditions. The energy costs of operating e-bikes are small, but there can be considerable battery replacement costs.
Range is a key consideration with e-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. The range of an e-bike is usually stated as somewhere between 7 km (uphill on electric power only) to 70 km (minimum assistance) and is highly dependent on whether or not the bike is tested on flat roads or hills. Some manufacturers, such as the Canadian BionX or American E+ (manufactured by Electric Motion Systems), have the option of using regenerative braking, the motor acts as a generator to slow the bike down prior to the brake pads engaging. This is useful for extending the range and the life of brake pads and wheel rims. There are also experiments using fuel cells. e.g. the PHB. Some experiments have also been undertaken with super capacitors to supplement or replace batteries for cars and some SUVS. E-bikes developed in Switzerland in the late 1980s for the Tour de Sol solar vehicle race came with solar charging stations but these were later fixed on roofs and connected so as to feed into the electric mains. The bicycles were then charged from the mains, as is common today.
There are two distinct types of controllers designed to match either a brushed motor or brushless motor. Brushless motors are becoming more common as the cost of controllers continues to decrease. (See the page on DC motors which covers the differences between these two types.)
Controllers for brushless motors: E-bikes require high initial torque and therefore models that use brushless motors typically have Hall sensor commutation for speed measurement. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. The controllers generally provide potentiometer-adjustable motor speed, closed-loop speed control for precise speed regulation, protection logic for over-voltage, over-current and thermal protection. 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.
Controllers for brushed motors: Brushed motors are also used in e-bikes but are becoming less common due to their intrinsic lower efficiency. Controllers for brushed motors however are much simpler and cheaper due to the fact they don't require hall sensor feedback and are typically designed to be open-loop controllers.
Not all e-bikes take the form of conventional push-bikes with an incorporated motor, such as the Cytronex bicycles which use a small battery disguised as a water bottle. Some are designed to take the appearance of low capacity motorcycles, but smaller in size and consisting of an electric motor rather than a petrol engine. For example the Sakura e-bike incorporates a 200 W motor found on standard e-bikes, but also includes plastic cladding, front and rear lights, and a speedometer. It is styled as a modern moped, and is often mistaken for one.
An Electric Pusher Trailer is an e-bike design which incorporates a motor and battery into a trailer that pushes any bicycle. One such trailer is the two-wheeled Ridekick.
Other, rarer designs include that of a 'chopper' styled e-bike, which are designed as more of a 'fun' or 'novelty' e-bike than as a purposeful mobility aid or mode of transport.
Various designs (including those mentioned above) are designed to fit inside most area laws, and the ones that contain pedals can be used on roads in the United Kingdom, among other countries.
E-bikes can be a useful part of cardiac rehabilitation programmes, since health professionals will often recommend a stationary bike be used in the early stages of these. Exercise-based cardiac rehabilitation programmes can reduce deaths in people with coronary heart disease by around 27%; and a patient may feel safer progressing from stationary bikes to e-bikes. They require less cardiac exertion for those who have experienced heart problems.
E-bikes are zero-emissions vehicles, as they emit no combustion by-products. However, the environmental effects of electricity generation and power distribution and of manufacturing and disposing of (limited life) high storage density batteries must be taken into account. Even with these issues considered, e-bikes will have significantly lower environmental impact than conventional automobiles, and are generally seen as environmentally desirable in an urban environment.
The environmental effects involved in recharging the batteries can of course be minimised. The small size of the battery pack on an e-bike, relative to the larger pack used in an electric car, makes them very good candidates for charging via solar power or other renewable energy resources. Sanyo capitalized on this benefit when it set up "solar parking lots," in which e-bike riders can charge their vehicles while parked under photovoltaic panels.
The environmental credentials of e-bikes, and electric / human powered hybrids generally, have led some municipal authorities to use them, such as Little Rock, Arkansas with their Wavecrest electric power-assisted bicycles or Cloverdale, California police with Zap e-bikes. China’s e-bike manufacturers, such as Xinri, are now partnering with universities in a bid to improve their technology in line with international environmental standards, backed by the Chinese government who is keen to improve the export potential of the Chinese manufactured e-bikes.
A recent study on the environment impact of e-bikes vs other forms of transportation found that e-bikes are about:
China's experience, as the leading e-bike world market, has raised concerns about road traffic safety and several cities have considered banning them from bicycle lanes. As the number of e-bikes increased and more powerful motors are used, capable of reaching up to 30 miles per hour (48 km/h), the number of traffic accidents have risen significantly in China. E-bike riders are more likely than a car driver to be killed or injured in a collision, and because e-bikers use conventional bicycle lanes they mix with slower-moving bicycles and pedestrians, increasing the risk of traffic collisions.
China has experienced an explosive growth of sales of non-assisted e-bikes including scooter type, with annual sales jumping from 56,000 units in 1998 to over 21 million in 2008, and reaching an estimated fleet of 120 million e-bikes as of early 2010. This boom was triggered by Chinese local governments' efforts to restrict motorcycles in city centers to avoid traffic disruption and accidents. By late 2009 motorcycles are banned or restricted in over ninety major Chinese cities. Users began replacing traditional bicycles and motorcycles and, in e-bike became an alternative to commuting by car. Nevertheless, road safety concerns continue as around 2,500 e-bike related deaths were registered in 2007. As of late 2009 ten cities have also banned or imposed restrictions on e-bikes on the same grounds as motorcycles. Among these cities are Guangzhou, Shenzhen, Changsha, Foshan, Changzhou, and Dongguang.
China is the world's leading manufacturer of e-bikes, with 22.2 million units produced in 2009. Production is concentrated in five regions, Tianjin, Zhejiang, Jiangsu, Shandong, and Shanghai. China exported 370,000 e-bikes in 2009.
Sales of e-bikes in Germany increased almost threefold between 2007 and 2012, from 70,000 to 388,000 units per year.
The first pedal-assisted bicycles appeared in Japan in 1993. In 2008, the sales of e-bike sales exceeded moped sales. In recent years, 2-passenger and even 3-passenger (two adults and a child) e-bikes were introduced in Japan.
The Netherlands has a fleet of 18 million bicycles. E-bikes have reached a market share of 10% by 2009, as e-bikes sales quadrupled from 40,000 units to 153,000 between 2006 and 2009, and the electric-powered models represented 25% of the total bicycle sales revenue in that year. By early 2010 one in every eight bicycles sold in the country is electric-powered despite the fact that on average an e-bike is three times more expensive than a regular bicycle.
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.
In 2012, two e-bike advocates completed the first 4,000-mile (6,400 km) transcontinental e-bike tour from New York to San Francisco to advocate for e-bikes in major cities across the U.S.
Many e-bikes in the United States are standard bicycles converted using a kit. In general, the kits include the motor (the majority of which are hub motors built into the front or rear wheel), a speed controller, throttle (usually twist-grip or thumb throttle), necessary wiring and connectors, and a battery. Several U.S. companies offer conversion kits, including EbikeKit.com and Ampedbikes.com. Major manufacturers also offer complete e-bikes such as Bmebikes  and Trek. Trek offers a line of e-bikes using the Bionx system in which the rider programs the controller to determine how much effort the motor will give in response to rider effort, from 25% up to 200% of the rider's power. This system ensures a minimum level of rider participation and is also used to comply with many European laws mandating partial human effort before the motor engages.
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