The bicycle's invention has had an enormous effect on society, both in terms of culture and of advancing modern industrial methods. Several components that eventually played a key role in the development of the automobile were initially invented for use in the bicycle, including ball bearings, pneumatic tires, chain-driven sprockets and tension-spoked wheels.[10]
Another style is the recumbent bicycle. These are inherently more aerodynamic than upright versions, as the rider may lean back onto a support and operate pedals that are on about the same level as the seat. The world's fastest bicycle is a recumbent bicycle but this type was banned from competition in 1934 by the Union Cycliste Internationale.[43]
After you decide which style of e-bike you want, consider the class. In the U.S., there are three classes defined by the type of assist and how fast the motor will propel you. Most electric bikes sold are class 1 or 3. Class 1 bikes have a motor (max 750w) that assists while you’re pedaling, up to 20 mph. Class 3, also known as “speed pedelec,” can also have up to a 750w motor, but it can assist you up to 28 mph. Both are allowed in most states and cities without requiring a license. Class 2 models have throttles that don’t require the rider to pedal in order to get a boost. They’re allowed on most streets, bike lanes, and paths, but are less popular than the other classes and not covered much here (because not only do we still love to pedal, we also prefer the greater distances that pedal-assist bikes can cover).
"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.
What's the Centros like? Big and heavy, but with enough power to overcome that, it really reminded me of a more upmarket Volt Pulse. You do tend to find that the weightier e-bikes give more of a feeling of speed, even though you're only doing 20mph or so at the absolute most (only up to 15mph with electrical assistance so you'll need leg muscles or a downward incline to get to that outlandish velocity).

Federal law in the United States states that an electric bicycle must have a top speed under 20 mph and a motor which produces less than 750 watts/1 hp. They are not considered motor vehicles by the federal government and are subject to the same consumer safety laws as unassisted bicycles.[11] Their legality on public roads is under state jurisdiction, and varies. See the main Electric bicycle laws article for details on the law in individual states.
In some countries mixed systems, i.e. pedaling and/or using a throttle is legal. In EU countries and Switzerland this is not the case. I.e. you can buy an electric scooter, but this is not considered to be an e-bike in the moped / light scooter category. That kind of hack is probably more difficult, unless the original design has been modified to fit with (s)Pedelec specs. E.g. The Ezee models are of that kind and modifications to revert to the original does not seem to be too difficult...

An electric bicycle is a bicycle with an electric motor used to power the vehicle, or to assist with pedaling. In many parts of the world, electric bicycles are classified as bicycles rather than motor vehicles, so they are not subject to the same laws as motor vehicles. Electric bicycles are one type of motorized bicycle. However, electric bicycles are defined separately and treated as a specific vehicle type in many areas of legal jurisdiction.

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.