In China, e-bikes currently come under the same classification as bicycles and hence don't require a driver's license to operate. Previously it was required that users registered their bike in order to be recovered if stolen, although this has recently been abolished. Due to a recent rise in electric-bicycle-related accidents, caused mostly by inexperienced riders who ride on the wrong side of the road, run red lights, don't use headlights at night etc., the Chinese government plans to change the legal status of illegal bicycles so that vehicles with an unladen weight of 20 kg (44 lb) or more and a top speed of 30 km/h (19 mph) or more will require a motorcycle license to operate, while vehicles lighter than 20 kg (44 lb) and slower than 30 km/h can be ridden unlicensed. In the southern Chinese cities of Guangzhou, Dongguan and Shenzhen, e-bikes, like all motorcycles, are banned from certain downtown districts. There are also bans in place in small areas of Shanghai, Hangzhou and Beijing. Bans of "Scooter-Style Electric Bikes" (SSEB) were however cancelled and in Shenzhen e-bikes may be seen on the streets nowadays (2010–11).
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.
EU: EN15194 (EPAC – Electrically Power Assisted Cycles) defines the use pedal-assisted less than 25k/h bikes: "Cycles with pedal assistance which are equipped with an auxiliary electric motor having a maximum continuous rated power of 0.25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25 km/h or if the cyclist stops pedaling.”
To qualify as an electric-assisted bicycle under state law they need to have a seat and fully operable pedals for human propulsion, meet federal motor vehicle safety standards, an electric motor that has a power output of not more than 1,000 watts, maximum speed of not more than 20 mph (electric motor and human power combined), disengages or ceases to function when the vehicle’s brakes are applied, two or three wheels
Range is a key consideration with e-bikes, and is affected by factors such as motor efficiency, battery capacity, efficiency of the driving electronics, aerodynamics, hills and weight of the bike and rider. Some manufacturers, such as the Canadian BionX or American Vintage Electric Bikes, have the option of using regenerative braking, the motor acts as a generator to slow the bike down prior to the brake pads engaging. This is useful for extending the range and the life of brake pads and wheel rims. There are also experiments using fuel cells. e.g. the PHB. Some experiments have also been undertaken with super capacitors to supplement or replace batteries for cars and some SUVS. E-bikes developed in Switzerland in the late 1980s for the Tour de Sol solar vehicle race came with solar charging stations but these were later fixed on roofs and connected so as to feed into the electric mains. The bicycles were then charged from the mains, as is common today. While ebike batteries were produced mainly by bigger companies in past, many small to medium companies have started using innovative new methods for creating more durable batteries. State of the art, custom built automated precision CNC spot welding machines created 18650 battery packs are commonly used among Do-it-yourself ebike makers.