Knowledge of electric bicycle
Motors and drivetrains
The two commonest kinds of hub motors utilized in electric bicycles are brushed and brushless. Many constructions are available, varys on cost and complication; direct-drive and geared motor units are all used. an electrical power-assist system could even be added to nearly all pedal cycle used chain drive, belt drive, hub motor or friction drive. BLDC hub motor is a typical modern design. The motor is formed into wheel hub, while the stator is fixed solidly to axle, and thus the magnets are attached to and rotating with the wheel. The bike wheel hub is the motor. the power grade of motors used are affected by available legal categories and are often, but not always limited to 750 watts below.
Another kind of electric assist motor, o ften be mentioned because of the mid-drive system, is increasing in popularity. in this system , electric motors are not built in wheel but are typically mounted near or under the lowest bracket shell. in additional typical configuration, a cog or wheel on the motor drives a belt or chain that runs with a pulley or sprocket fixed to a minimum of one among the arms of the bicycle’s crankset. Therefore the propulsion/force is provided at the pedals rather than at wheel, being eventually applied to the wheel through the bike’s standard drive train.
As power is offered from chain and sprocket, it is generally limited to 250watts to 500 watts in order to defend against quick decrease of drivetrain. an electrical mid drive combined with an inside gear hub at the rear hub may require care because of the shortage of a clutch mechanism to melt the shock to the gears at the moment of re-engagement. A continuously variable transmission or a totally automatic innner gear hub probably decrease the shocks because of viscosity of oils used for liquid coupling instead of the mechanical couplings of the normal internal gear hubs.
Controllers
There are two different kinds of controllers to adapt brushed motor and brushless motor. Brushless motors are now getting more popular because of decrease of value of controllers.
Brushless motor: electric bikes require high initial torque/power and bicycles which use brushless motors generally have Hall sensor commutation for speed and angle measuring. An electronic controller provides support as a function of the sensor inputs, the bikes speed and thus the specified propulsion/force. The controller generally allow input through potentiometer or Hall Effect twist grip, closed loop speed controller for accurate speed adjustment, protection logic module for over voltage, over current and so on. Bicycles with a pedal assist function generally contain a disc at the crank shaft and feature a hoop of magnet that contain Hall sensor offer increase to pulses, the frequency is proportional applied to pedaling speed. The controller controls power to the motor with pulse width modulation. from time to time the support is provided for regenerated and unusual braking and therefore low mass of bicycles limits energy recovery.
Brushed motor: Brushed motor is also used in electric bikes but it is getting less used because of the lower efficiency. Controllers for brushed motor however are much simpler and cheaper because of the actual fact they don’t require hall sensor feedback and are generally designed to be open loop controllers. Some of the controllers can handle multiple voltages.
Batteries
Electric bikes utilize rechargeable battery, powerful motor and a few sort of control. Battery types include sealed lead-acid (SLA), nickel-cadmium (NiCad), nickel-metal hydride (NiMH) or lithium-ion polymer (Li-ion). Batteries vary consistent with the voltage, total charge capacity (amp hours), weight, the amount of charging cycles before performance degrades, and skill to handle over-voltage charging conditions. The energy costs of operating e-bikes are small, but there are often considerable battery replacement costs. The lifespan of A battery pack varies counting on the sort of usage. Shallow discharge/charge cycle will help to stretch battery lifespan.
Range may be a key consideration with electric bikes, and is influenced by motor efficiency, battery capacity, driving electronics efficiency, aerodynamics, hills and weight of the bicycle and rider.Some manufacturers, like American Vintage Electric Bikes,have the chance of selecting regenerated brake, the motor performs as a generator to retard the bike before the restraint engage. this is often useful for extending the range and therefore the lifetime of restraint and wheel rims. While electric bicycle battery was produced mainly by big companies in the past, many small to medium companies started to use innovative new method to create more durable and stable batteries.
