Electric bicycle

An electric bicycle, also known as an e-bike, powerbike or booster bike, is a bicycle with an integrated electric motor which can be used for propulsion. Many kinds of e-bikes are 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 ones can travel up to 25 to 32 km/h (16 to 20 mph), depending on local laws, while the more high-powered varieties can often do in excess of 45 km/h (28 mph). In some markets, such as Germany as of 2013, they are gaining in popularity and taking some market share away from conventional bicycles, while in others, such as China as of 2010, 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. This exempts them from the more stringent laws regarding the certification and operation of more powerful two-wheelers which are often classed as electric motorcycles. E-bikes can also be defined separately and treated under distinct Electric bicycle laws.

E-bikes are the electric motor-powered versions of motorized bicycles, which have been in use since the late 19th century. Some bicycle-sharing systems use them.

Operation
The VAE is a bike that has electric assistance. This assistance aims to provide a complement to pedaling. It consists of a motor, a battery, a controller and sensors.

The sensors detect the presence of pedaling, its cadence, the force exerted on the pedals, the position of a possible accelerator, and braking.

A controller incorporates the parameters that qualify the bike’s behavior according to the user’s profile chosen by the manufacturer. It regulates the current consumption and controls the motor in its various phases of operation: starting, continuous speed, acceleration, etc. from the information transmitted by the sensors.

The user has, depending on the model, the possibility of cutting or dosing the level of assistance while driving, through a selector or an “accelerator”.

On some hub-motor bikes, the battery is automatically charged with braking and downhill. Braking is facilitated by the engine brake.

Engines
Hub motor: easy to install, it fits in place of a front or rear wheel axle.
Remote motor: the transmission is done by a belt or a chain acting on a transmission plate placed on the axis of a wheel. The position of the motor is free.
Pedal motor: it acts directly on the axis of the pedal of the bicycle. It consists of a block comprising all the components of electric traction: the engine, the sensors and the control electronics. It can only be installed on a specific frame.
Friction motor: roller friction motor on the tread of the front or rear tire. It was used on the Solex moped.

Batteries
For VAE, the lithium battery is mainly used; the other technologies, lead or nickel, have been progressively abandoned on VAE marketed in Europe.

The weight of the battery, long problematic, today benefits from significant improvements related to Lithium Ion and Lithium Polymer. Thus, a lead battery weighs about 13 kg, while a lithium battery weighs about 3 kg for equivalent voltage and capacity.

The full charge of the battery takes 3 to 8 hours depending on the technology of the battery and charger. Fast refills are possible with appropriate chargers and batteries. These types of accumulators do not support deep discharges, so it is advisable to recharge them as often as possible, or even to remain in charge during periods of non-use, modern chargers being particularly well studied for these cases.

Under the name “Lithium” exist several technologies with substantially different characteristics. In 2015, LiE-Ion, Lithium Polymer (LIPO) and LiFePO4 batteries are mainly used on the VAE. The first two technologies make it possible to obtain batteries that are very light but sensitive to cold and heavy loads / discharges. LiFePO4 is considered safer (fire), it accepts higher charging currents (lower recharge time) and above all it has a longer life (a thousand cycles and more).

The battery remains one of the weak points of the electric bike, as for electric cars. Even outside of its theoretical life, it is easy not to properly manage this element, and the replacement price is very important, several hundred euros for a lithium battery.

The battery of an electric bike is sensitive to temperature differences: manufacturers give an ideal temperature range in order to have the best possible autonomy.

Batteries are sensitive to shock: chemicals are contained in fragile envelopes that can pierce and even ignite.

Classes
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:

With pedal-assist the electric motor is regulated by pedalling. The pedal-assist augments the efforts of the rider when they are pedalling. These e-bikes – called pedelecs – have a sensor to detect the pedalling speed, the pedalling force, or both. Brake activation is sensed to disable the motor as well.
With power-on-demand the motor is activated by a throttle, usually handlebar-mounted just like on most motorcycles or scooters.

Therefore, very broadly, e-bikes can be classed as:

E-bikes with pedal-assist only: either pedelecs (legally classed as bicycles) or S-Pedelecs (often legally classed as mopeds)
Pedelecs: have pedal-assist only, motor assists only up to a decent but not excessive speed (usually 25 km/h), motor power up to 250 watts, often legally classed as bicycles
S-Pedelecs: have pedal-assist only, motor power can be greater than 250 watts, can attain a higher speed (e.g., 45 km/h) before motor stops assisting, legally classed as a moped or motorcycle (not a bicycle)
E-bikes with power-on-demand and pedal-assist
E-bikes with power-on-demand only: often have more powerful motors than pedelecs but not always, the more powerful of these are legally classed as mopeds or motorcycles

Pedal-assist only
E-bikes with pedal-assist only are usually called pedelecs but can be broadly classified into pedelecs proper and the more powerful S-Pedelecs.

Pedelecs
The term “pedelec” (from pedal electric cycle) refers to a pedal-assist e-bike with a relatively low-powered electric motor and a decent but not excessive top speed. Pedelecs are legally classed as bicycles rather than low-powered motorcycles or mopeds.

The most influential definition of pedelecs and which are not comes from the EU. EU directive (EN15194 standard) for motor vehicles considers a bicycle to be a pedelec if:

the pedal-assist, i.e. the motorised assistance that only engages when the rider is pedalling, cuts out once 25 km/h is reached, and
when the motor produces maximum continuous rated power of not more than 250 watts (n.b. the motor can produce more power for short periods, such as when the rider is struggling to get up a steep hill).

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 non-European jurisdictions (such as the state of Victoria in Australia).

Pedelecs are much like conventional bicycles in use and function — the electric motor only provides assistance, for example, when the rider is climbing or struggling against a headwind. Pedelecs are therefore especially useful for people 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 for riders who more generally need some assistance, e.g. for people with heart, leg muscle or knee joint issues.

S-Pedelecs
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. In the United States, many states have adopted S-Pedelecs into the Class 3 category. Class 3 ebikes are limited to