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).
Speaking of which, if you're used to non-electric cycles, be aware that e-bikes are heavy and capped at 25kph or 15.5mph. In many cases, that means the bike starts to feel like its actively fighting against you, if you try to push the speed higher than that by pedalling. That's especially true with heavier bikes, for obvious reasons, and can take a while to get used to. 
This slick-looking commuter features a clean and quiet Gates Carbon Drive belt, which eliminates the maintenance that comes with a derailleur, and an internally geared Enviolo Trekking hub, which provides a 380 percent gear range. The Embark has 650b wheels, 47mm WTB gumwall tires, full fenders with mudflaps, and integrated lights—meaning you can ride long after the sun sets—or before it rises. A Bosch Active Line Plus mid-drive motor is light and quiet and provides pedal assist up to 20 mph, and the Bosch 400Wh battery has a claimed range of 50 miles. Everything about the Embark frame screams clean, stylish, and organic.
I had gotten this to build an electric bike but I have never worked with wires before so I didn't realize that we needed to attach our own connectors to the wires. The person who I talked to at Joyisi was super nice and explained that to me and even offered to send me connectors for free. I had already ended up getting a different bike altogether though and so I just wanted to return the battery. But because I am returning it for my own reasons (as opposed to the battery being faulty), they would normally have me pay for return shipping and deduct the cost of shipping to me (which is a lot, because they are international) and the inspection fee from my refund, but they were super nice and offered to take on most of the costs and I would only have to pay for the return
Electric-assisted bicycles are treated as human-powered bicycles, while bicycles capable of propulsion by electric power alone face additional registration and regulatory requirements as mopeds. Requirements include electric power generation by a motor that cannot be easily modified, along with a power assist mechanism that operates safely and smoothly. In December 2008, The assist ratio was updated as follow:

Around the turn of the 20th century, bicycles reduced crowding in inner-city tenements by allowing workers to commute from more spacious dwellings in the suburbs. They also reduced dependence on horses. Bicycles allowed people to travel for leisure into the country, since bicycles were three times as energy efficient as walking and three to four times as fast.

As with all these bikes, the assisted speed is capped at 15mph, but unlike some of them, the Gtech eBike City or its identical (spec-wise) sibling the eBike Sport (this just has a standard frame rather than a step-through one) is light and agile enough for you to be able pedal harder without feeling like the weight is fighting you back down to 15mph. You can even, at a push, use it without the motor on flatter roads.
Speaking of which, if you're used to non-electric cycles, be aware that e-bikes are heavy and capped at 25kph or 15.5mph. In many cases, that means the bike starts to feel like its actively fighting against you, if you try to push the speed higher than that by pedalling. That's especially true with heavier bikes, for obvious reasons, and can take a while to get used to. 
Generally they are considered vehicles (like motorcycles and pedal cycles), so are subject to the same rules of the road. Regulations may define maximum power output and for electric bikes may or may not require an interlock to prevent use of power when the rider is not pedaling. In some cases regulatory requirements have been complicated by lobbying in respect of the Segway HT.
The federal law will not prohibit a motor vehicle label and additional restrictions given by the state. States will typically define e-mopeds in the 1000W range (1.5 hp) and speeds attainable to 30mph, and include a few requirements such as a helmet, eye protection, and a driver’s license. States may also require title, registration, and insurance for mopeds.
The battery is the pedelec’s power source. It supplies the motor with the electrical energy that is required to provide power assistance when cycling. So it is hardly surprising that there is frequent discussion and “talking shop” about the eBike’s battery in particular. What is the difference between batteries? How far can you go on a fully charged battery? What do you have to remember about storage? Thomas Raica, head of technical customer application, here provides information and advice.

GPS Firmware: This net update will be much appreciated by people who have a GPS Analogger device with their CA3. With a simple hardware modification to the Analogger circuit, the GPS data will be transmitted from your existing TRS cable back to the Cycle Analyst. You can then see the time of day, your elevation, position, and direction all on the CA3 screen. The firmware also features additional custom views on the main screen, allowing you to replace or toggle the battery voltage with any of these new parameters to get just the display you are after.
Electric-assisted bicycle operators must follow the same traffic laws as operators of motor vehicles (except those that by their nature would not be relevant). The bicycles may be operated two abreast. Operators must generally ride as close as is practical to the right-hand side of the road (exceptions include when overtaking another vehicle, preparing for a left turn, and to avoid unsafe conditions). The bicycle must be ridden within a single lane. Travel on the shoulder of a road must be in the same direction as the direction of adjacent traffic.
None of this would matter if the VanMoof Electrified S2 (and its close relative the X2) wasn't fun to ride, but it is a blast. Like the Brompton, it pulls off the neat trick of powering you along but giving the illusion that you're doing the work, reacting quickly and cleverly to the speed of your pedalling and the difficulty of any incline you're on. 
Having spent some quality time with Wing’s e-bike, I understand why so many people are excited about the growing popularity of electric-powered vehicles like bikes and scooters. They take a lot of the work out of getting from point A to point B, while retaining all of the joy. They can give you more confidence when navigating a treacherous city terrain that prioritizes cars over people. And let’s face it: bikes are cool, and always will be.
Class 1 makes great inroads to establish set boundaries for off road/natural surface trail access for eMountain bikes. There is fierce resistance from some mountain biking purists to allow ebikes on trails. BPSA and IMBA have done good work to justify the impact of class 1 ebikes on natural surface trails, and eliminate the wear-n-tear argument, though IMBA members are not 100% on board.
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.[63] The rules for e-bikes on public roads, sidewalks, and pathways are under state jurisdiction, and vary.
The $3,099 MSRP is a bit daunting if you've not shopped for high-end bikes before, but it compares favorably with, say, Trek's electric bike lineup. That said, you can get a solid urban/commuter bike without a motor for well under $1,000. You can even score an e-bike for under a grand, but you'll likely be looking at a battery range of less than 40 miles, along with lower-quality components.
As long as the electric bicycle meets three criteria it is considered a low-speed electric bicycle, or simply a "bicycle." Three criteria: must travel less than 20 mph on flat ground without pedaling, must have functional pedals and must have less than a 750 watt motor. This is the same criteria as Federal Public Law 107-319. I checked my facts with the law office of Spohn, Spohn & Zeigler at 144 East Center Street, Marion, OH 43302 on August 21, 2009. A low-speed electric bicycle does not require registration, insurance, license plates (tags), or a driver's license. The rules of an electric bicycle are the same as a traditional bicycle. There is some confusion caused by Ohio interchanging the word Moped with "motorized bicycle." If a dealer sells you a bike that follows the guidelines of Federal Public Law 107-319, then you have a bicycle. If the bike has no pedals or has a higher wattage motor than 750 watts or can travel faster than 20mph you have a moped or scooter; Ohio requires tags and registration for mopeds and scooters.
Haibike ships the HardNine with 29-inch tires, 180-millimeter hydraulic disc brakes, a 100-millimeter front suspension fork, and a nine-speed Shimano shifting system. The bike’s LCD readout is affixed to the handlebars and displays the current speed, level of charge, remaining range, and current pedal assist mode. The company says the battery can be completely recharged in just four hours, minimizing downtime between rides.