The "Dandy horse", also called Draisienne or Laufmaschine, was the first human means of transport to use only two wheels in tandem and was invented by the German Baron Karl von Drais. It is regarded as the modern bicycle's forerunner; Drais introduced it to the public in Mannheim in summer 1817 and in Paris in 1818.[18][19] Its rider sat astride a wooden frame supported by two in-line wheels and pushed the vehicle along with his or her feet while steering the front wheel.[18]
The Christmas day is coming soon, since I receive the bike, it's about a week, and I am satisfied with it! just as advertised, very powerful and good design. the most important point is that once the battery is FULL CHARGE, how far it can reach up to. I have a funny test, in the normal road(not in the dramatic slope or uphill), it can goes almost 44 miles. That is what I give 5 star for this bike! very powerful with reasonable price!
"Bicycles" and "Electric Bicycles" are legally defined in the Texas Transportation Code Chapter 551., titled "Operation of Bicycles, Mopeds, and Play Vehicles" in Subchapter A, B, C, and D.[58] The following definition of electric bicycle was passed by the Texas legislature in 2001. "Electric bicycle" means a bicycle that is designed to be propelled by an electric motor, exclusively or in combination with the application of human power, cannot attain a speed of more than 20 miles per hour without the application of human power; and does not exceed a weight of 100 pounds. The department or a local authority may not prohibit the use of an electric bicycle[0] on a highway that is used primarily by motor vehicles. The department or a local authority may prohibit the use of an electric bicycle[0] on a highway used primarily by pedestrians.
It’s a topic that many eMTBers are interested in: fast charging. What has long been a reality with electric cars is now also being partly improved for ebikes with high amperage chargers. Bosch has presented a 6A charger this year that can charge a 500 Wh battery in 3 hours, more than a third faster than the standard charger. The new benchmark next year, however, will probably be the 10A charger presented by Haibike and BMZ. It is claimed to be capable of charging a 630 Wh battery in just 1.5 hours.
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.

One of the most important categories of ebikes is the low-cost, entry-level sector. What I call the eBigBox models.  Obviously, not everyone can’t afford a $7500 Riese and Muller and frankly a lot of people are skeptical on how much they will use and enjoy an ebike. So even if they can afford a few thousand dollars for an ebike, they might not want to put it all down on a category they aren’t sure about.
On the road, it takes only a few turns of the pedals to activate the Vado’s motor and get it up to speed. In Turbo mode — the bike’s highest level of pedal-assist — the Vado reaches speeds of up to 28 miles per hour, after which the electric drive system automatically shuts off to conserve power (and abide by local law). A built-in LED readout on the handlebars allows riders to monitor battery life, check current speed, and track calories burned while also being able to glance at distance traveled. The Turbo Vado Mission Control app (iOS/Android) also connects to the bike via Bluetooth and allows riders to further tune their ride and adjust the bike’s settings.

Perhaps the cleverest thing of all about the Electric Brompton is that despite all the extra stuff, it folds up exactly the same as the non-powered variety. It's so simple, and unlike certain folding bikes we could mention, what you're left with is a genuinely small thing, rather than something that's about the size of a bike with the front wheel taken off.