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.[43]

Some electric bikes claim to use a neat trick called regenerative braking. If you start pedaling the bicycle or going downhill, the spinning wheels turn the electric motor in the hub in reverse and start charging up the batteries. In practice, regenerative braking is nowhere near as useful on an electric bicycle as it is on an electric train or car. An electric bike has much less mass and velocity than either a train or car, so it never gains (or loses) anything like as much kinetic energy when it starts and stops. You'd have to go down an awful lot of hills to charge up the batteries completely and that's usually not practical. And what's the point in pedaling the wheels simply to charge the battery? You might as well have bought an ordinary bicycle to start with!
Would an e-bike that used a trailing generator to power the electric motor still be considered an e-bike? The purpose of the generator is allow greater distances to be traveled and all day riding. The gen-set that I am looking at uses a 49 cc gas engine with a 12 volt generator, this would be from the ground up build using a 1 hp electric motor. This seems to stay within the state laws of AZ. where I reside. Thanks for your thoughts.
Yes, there are less expensive ebikes on the market but most come with a few serious caveats. The Espin Sport delivers on the full promise of an electric bike, but in a more affordable fashion. This bike isn’t going to tow you around for a 60-mile round-trip endeavor but those seeking their first ebike will get plenty of return on their investment with this model.
In addition, Kalk weighs under 155 pounds — less than half of traditional motorbikes. Cake customized parts of the drivetrain and implemented an interior permanent magnet (IPM) motor. On a single charge, the bike travels up to 50 miles and as a bonus feature, maintenance is minimal due to the fact there are few moving parts thanks to its lack of a combustion engine.
Electric-assist and other "motorized bicycles"[86] do not need to be inspected, do not require a license, and do not require registration. The vehicle must meet all of the following criteria: a post mounted seat for each person it is designed to carry, two or three wheels which contact the ground, fully operative pedals, wheels at least 16 inches in diameter and a motor not capable of propelling the device at more than 20 mph on level ground. The driver does not need a license, but must be at least 16 years old. DC law prohibits motorized bicycles from traveling anywhere on the sidewalk or in the bike lanes. DC Regulation 18-1201.18 provides: "Except as otherwise permitted for a motor vehicle, no person shall operate a motorized bicycle on any sidewalk or any off-street bikepath or bicycle route within the District. This prohibition shall apply even though the motorized bicycle is being operated solely by human power." So, if cars are prohibited in a particular place, motor-assisted bikes are also prohibited.[87]
Some argue, that an ebike should have some kind of front suspension, i.e. be able to cope with potholes at higher speed or off-road conditions. However, in countries with flat roads (e.g. Switzerland, Germany or Holland) you don't need that extra weight for extra price if you stay on roads and/or drive slowly in difficult terrain. Some makes (like the Stromer) let you choose.
Most consumers want an e-bike that will accommodate its motor without being too cumbersome and will remain stable in spite of its electronic components. Some consumers want only the most basic of e-bike features, including lights, a cargo rack/basket, and a water bottle holder. Others are focused more heavily on safety features, such as brake type. And still others are concerned with convenience and portability.
While we're still fairly new to the solar ebike game, Mark is among the (suprisingly numerous) Grin customers who've been thinking about and experimenting with solar bikes for many years. After he shared pictures of his latest project and mentioned his round the world touring ambitions, we thought we had to do a small feature on this guy. A quick last minute trip to Maker Faire was arranged to meet up, and here we present, Mark Havran:
Gearless (Direct-Drive) Hub Motors – Some conversion kits (and bikes) use gearless, direct-drive motors. On this type of motor, the axle that passes through the center of the motor is actually the axle of the motor itself, with the copper windings fixed to the axle. The magnets are mounted to the outer shell of the hub motor. When electricity is applied to the stator a magnetic field is induced that causes the magnets to move. This in turn makes the whole shell of the motor turn and propels the e-bike forward. Even though corrosion will eventually have an impact, this type of motor should last for years since there’s no gearing and no contact between moving parts. They’re also capable of higher top speeds. But since there’s no gears, they have less torque and it requires more power to get the motor up to speed. Most direct-drive hub motors are 350w-500w and reach speeds of 18-25 mph. But more powerful motors can reach speeds of 35+ mph.

What we especially love is how quiet this e bicycle is. If you’re riding down the street or through the park, the gentle hum of the motor is unnoticeable. This is because it’s hidden by the sound of your smooth pedaling. If you’re not into flashy gadgets, any ordinary person would assume you’re riding a conventional peddle bike. This is a great commuter bike.

"Bicycle" means either of the following: (1) A device having two wheels and having at least one saddle or seat for the use of a rider which is propelled by human power. (2) A device having two or three wheels with fully operable pedals and an electric motor of less than 750 watts (one horsepower), whose maximum speed on a paved level surface, when powered solely by such a motor while ridden, is less than 20 miles per hour.
Even the humble bicycle hasn't escaped the clutches of modern technology. A whole herd of new e-bikes with electric motors are taking to our cities' streets. Adding a motor to a standard cycle does ramp up the price significantly, but it takes much of the effort out of cycling, making your commute to the office a sweat-free experience and allowing you to sit back and enjoy your suburban cruise.
We've also released our first native 72V battery pack in a conventional downtube battery casing, assembled using the high power Samsung 27100 40T cells so that even with the small 8Ah capacity it is able to deliver 40-50A continuous currents. This is an ideal battery for fast and sporty offroad ebike builds, allowing powerful performance without the weight or complexity of most 72V setups (either two 36V packs in series or a large triangle frame battery).
Some US companies, notably in the tech sector, are developing both innovative cycle designs and cycle-friendliness in the workplace. Foursquare, whose CEO Dennis Crowley "pedaled to pitch meetings ... [when he] was raising money from venture capitalists" on a two-wheeler, chose a new location for its New York headquarters "based on where biking would be easy". Parking in the office was also integral to HQ planning. Mitchell Moss, who runs the Rudin Center for Transportation Policy & Management at New York University, said in 2012: "Biking has become the mode of choice for the educated high tech worker".[66]