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!

But the good times of the stealthy ebike existence will not endure forever. The ebike market is growing steadily and more so, technology is driving performance up and costs down. The market for a green, lifestyle friendly, transportation technology, with GPS, theft ID, cell service and probably skim lattes is alive and driving an emerging market. It is a matter of time before we all must face and respond to the legal demands of the state and local laws. Not to be over obligatory about being legal and duty oriented, but I do call on my fellow ebikers to ride legal, whether ebike, moped or other. Go ahead and build the 1200W ebike of your dreams, but get it insured and licensed if you must. Such compliance will set the precedence for public acceptance of ebikes in general, and build a track record for expansion and mainstreaming of moped-speed ebikes for commuter value driven needs of the future.

A "class 1 electric bicycle," or "low-speed pedal-assisted electric bicycle," is a bicycle equipped with a motor that provides assistance only when the rider is pedaling, and that ceases to provide assistance when the bicycle reaches the speed of 20 miles per hour. (2) A "class 2 electric bicycle," or "low-speed throttle-assisted electric bicycle," is a bicycle equipped with a motor that may be used exclusively to propel the bicycle, and that is not capable of providing assistance when the bicycle reaches the speed of 20 miles per hour. A "class 3 electric bicycle," or "speed pedal-assisted electric bicycle," is a bicycle equipped with a motor that provides assistance only when the rider is pedaling, (no throttle) and that ceases to provide assistance when the bicycle reaches the speed of 28 miles per hour, and equipped with a speedometer. Local government ordinances are allowed to permit or ban any class of electric bicycles on dedicated bicycle paths and trails, with Class 1 & 2 permitted, and Class 3 banned, by default.
It is very important that sensors work well and that they are integrated/tuned for good usability. Although ebikes do need some initial mental adjustment from riders, some model do much better then others, e.g. most testers seem to prefer the TDS Impluse over the Stöckli E.T. over the Stromer (which model?) with respect to reactivity. Of course, usability is subjective and some people may prefer one behavior over an other. However, cheap bikes may be just plain bad and this is why test driving is important.

I eventually got used to it over time, but at first having both kids behind me made the bike feel like it would sway to or fro perilously. I think it was just too much weight to navigate safely, and would be fine with younger kids that didn’t come close to the 120-pound weight limit for the rear cargo area. Overall I’m still a bit partial to a box-style bike if I’m hauling multiple kids and want to be able to see what they’re doing.

Electric Motorcycles News (EMN) has been launched in March 2017 and is a personal initiative from graphic designer Guy Salens (Belgium) to inform you about electric motorcycles, electric scooters and some offroad performance e-bikes. EMN collects and publishes all kind of info from available sources on the internet: press releases, existing website content from manufacturers. EMN has also developed a search engine where you can search for e-dealers with your specific keywords, in different countries, different brands and/or categories.
A human traveling on a bicycle at low to medium speeds of around 16–24 km/h (10–15 mph) uses only the power required to walk. Air drag, which is proportional to the square of speed, requires dramatically higher power outputs as speeds increase. If the rider is sitting upright, the rider's body creates about 75% of the total drag of the bicycle/rider combination. Drag can be reduced by seating the rider in a more aerodynamically streamlined position. Drag can also be reduced by covering the bicycle with an aerodynamic fairing. The fastest recorded unpaced speed on a flat surface is 144.18 km/h (89.59 mph)[41]

But the whole is also influenced by the sensory systems which are very different from model to model. E.g. A typical 2013 Panasonic system requires pedalling for optimal support (55/minute?) and has both a pedalling frequency and a speed sensor. You don't get much assistance if you pedal very slowly or very fast. Typically, a rear motor has a force sensor, i.e. you get lots of support fast when you start pedalling in a low gear, i.e. it will "feel" your need for assistance.
As is the case with any e-bike assembled from Chinese parts, Wing has its share of clones that can be found for sale on sites like IndieGoGo and Kickstarter. For example, the Danish company Strom Bikes has a model for city biking that also looks incredibly similar to Wing’s Freedom — and is apparently several hundred dollars cheaper too. This is also commonly found with electric scooters, with startups buying Chinese-made models and rebadging them for sale in the US.
What I found most interesting is how my cycling habits changed over my two weeks with the eBike, mostly for the better. In most states, cyclists need to come to a complete stop at stop signs... and as anyone who has ever ridden a bike or shared a road with a cyclist knows, most cyclists generally do an Idaho Stop if they believe it's safe. I do it, too. Knowing that I could quickly get back up to speed with the aid of the electric motor, I found myself more willing to sacrifice my forward momentum and come to a complete stop when there was a car approaching an intersection.
Beginning January 1, 2017, manufacturers and distributors of electric bicycles will be required to apply a label that is permanently affixed, in a prominent location, to each electric bicycle, indicating its class. Should a user "tamper with or modify" an electric bicycle, changing the speed capability, they must replace the label indicating the classification.
On the other hand, the battery doesn’t lock into the bike, which means you can’t just leave it on your bike when you park at the bike rack. Anyone could walk by and simply remove your battery. That seems like an oversight to me, though perhaps the designers assumed that such a small battery would just be easy to take with you. And it is. My wife could probably lose this battery in her purse.