E-bikes mostly use motors and battery options from a few major suppliers: Bosch, Yamaha, Shimano, and Brose. A few other brands exist, but are less reliable or powerful. Some, like the Yamaha system, have more torque, and others, like Bosch’s Active Line, are nearly silent. But, generally, all four make good options. Look for motor output (in torque), which will give you an idea of total power. Just like car engines, more torque equals more power off the line and more boost to your pedaling. But watt hours (Wh) is perhaps a more important figure to use—it takes into account battery output and life to give a more accurate reflection of power (higher Wh equals bigger range).
Rad Power’s lineup of 2019 bikes start at $1,699 (there’s also a Cyber Monday special on their 2018 models), proving that electric bikes don’t have to be over $2,000 to have the amenities and quality you need for daily commuting. Of course, that’s still a steep price for some. But as prices keep dropping in the e-bike industry, affordability breeds better access, and this might be the key that our cities—and their traffic—so desperately need.
The batteries are the most important parts of the bike, because (if you don't do any pedaling) they contain all the power that will drive you along. Typical electric bike batteries make about 350–500 W of power (that's about 35–50 volts and 10 amps), which is about a quarter as much as you need to drive an electric toaster. In theory, you could use any kind of battery on a bicycle. In practice, however, you want to use something that stores lots of power without being too heavy—or you'll be using half your power just moving the battery along! That tends to rule out heavy lead-acid batteries like the ones that start cars, though some electric bikes do use them. Lightweight lithium-ion batteries, similar to those used in laptop computers, mobile (cellular) phones, and MP3 players, are now the most popular choice, though they're more expensive than older rechargeable battery technologies such as nickel-cadmium ("nicad"). Typical batteries will give your bicycle a range of 10–40 miles between charges (depending on the terrain) and a top speed of 10–20 mph (which is about the maximum most countries allow for these vehicles by law). You can extend the range by pedaling or free-wheeling some of the time.
I converted my Kona Dew Deluxe to electric with a controller and 1000 watt front wheel. The SLA batteries I tried initially were _functional_, but the bike had a range of about 6 miles @ approx. 50% throttle use. Since upgrading to the Joyisi pack, the utility of the bike has increased exponentially. I need to add a better gauge so I can drain the battery more fully between charges, but I'm getting at least 20 miles per charge, including some very aggressive uphill segments. On flat ground, the battery powers the bike to approx. 35MPH; even on really steep hills with minimal pedal assist, I do at least 15MPH. Biking 15MPH uphill with little/no effort is EPIC.
In the 1890s, electric bicycles were documented within various U.S. patents. For example, on 31 December 1895 Ogden Bolton Jr. was granted Template:US Patent for a battery-powered bicycle with “6-pole brush-and-commutator direct current (DC) hub motor mounted in the rear wheel.” There were no gears and the motor could draw up to 100 amperes (A) from a 10-V battery.
No endorsement is required on a driver license in order to operate a motorized bicycle, thus the motorized bicycle may be operated by anyone with a valid driver license. Goggles, windshields and other special equipment required for motorcycles and motor-driver cycles are not required for operation of a motorized bicycle. However, crash helmets are required regardless of operators age. Minors between the ages of 14 and 16 may apply for a restricted license to operate a motorized bicycle, just as they would to operate a motor-driver cycle. For instance, they must take a written test, vision tests and demonstrate their ability to operate the motorized bicycle. The license issued will be restricted to a motorized bicycle only. The license is valid only during daylight hours and within a seven-mile (11 km) radius of the driver's home. Applicants for any type of license less than eighteen (18) years old, must complete a Minor/Teen-age Affidavit and Cancellation form making the parent or legal guardian financially liable for the applicants action. 
Bike is awesome, warranty support has so far delivered, but is a hassle to deal with (and hassle is acceptable and better than nightmare, or unresponsive/clueless/unhelpful/not-english-speaking). To be fair, this is the middle of Swag's busy season. Check tire inflation, check and tighten fasteners, seatpost and handlebars and stem out of the box, RTFM, charge the battery and you're out the door riding quickly.
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.
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.
The federal Consumer Product Safety Act defines a "low speed electric bicycle" as a two or three wheeled vehicle with fully operable pedals, a top speed when powered solely by the motor under 20 mph (32 km/h) and an electric motor that produces less than 750 W (1.01 hp). The Act authorizes the Consumer Product Safety Commission to protect people who ride low-speed electric vehicles by issuing necessary safety regulations. The rules for e-bikes on public roads, sidewalks, and pathways are under state jurisdiction, and vary.