FAQ's

Q: What are the advantages of electric bikes?

Q: How do e-bikes work?

Q: How do electric bikes perform?

Q: What is an electric bicycle?

Q: What size or power of the motor is needed and what is best?

Q: What kinds of battery are available and how long can I use bicycle before the battery runsout?

Q: What is the electrical consumption like?

Q: How fast can I go on an electric bicycle?What are the legal issues involved in owning one?

Q: How should I correctly use and maintain my electric bicycle?

Q: How about after sales support?

"In a systematic energy flow comparison, a grid-charged battery driving an electric motor will provide mechanical energy about ten times more efficiently than a human eating a typical US diet. For personal travel between 5 and 30 miles per day, the electric bicycle offers the lowest environmental and personal monetary cost, usually without increasing urban travel time"
From Energy,Global Warming, and Electric Bicycles
Energy Flow Analysis with an Emphasis on Personal Transportation

1. Hill Climbing
That may sound obvious, but its the primary advantage. A good electric bike effectively flattens hills, increasing your average speed and eliminating the groan factor when a gradient comes into view. Provided you supply a reasonable amount of effort, you can expect to climb hills of 1 in 10 (10%) on an electric bike with ease, and clear a maximum gradient of 1 in 7 (14%), or much more. In hilly country, the effect is nothing short of miraculous.

2. Safety
It sounds unlikely, doesnt it? But the mathematics is compelling. Think of a steep and busy road, with cars climbing at 30mph. If you previously slogged up the hill at 6mph, but can tackle the same gradient at 12mph with an electric bike, you will see 33% fewer cars, and they will pass you at 18mph rather than 24mph. Or at least, we think thats correct.

Whatever the figures, theres no doubt that an electric bike helps to keep you out of danger. The same general principle applies to road junctions - the faster your acceleration, the sooner you can get out of trouble. And with no need to rush the hills, you wont be tempted to ride downhill at breakneck speed... another useful safety feature.

3. Personal Fitness
Surely a conventional bike will keep you fitter? That, of course, depends how much - if at all - you use it. Research (b) has found that 46% of conventional bikes are used only once or twice a week, with a further 30% being used once a fortnight or even less. By contrast, a recent survey of electric bicycle owners reveals that a third ride their bike at least once a day and 81% use the bike at least once a week (c).

The figures confirm our experience that an electric bike typically gets used at least twice as often as a conventional machine.

Because riding an electric bike is a great deal more enjoyable in hilly country, into strong winds, or when carrying heavy loads, users tend to make better use of them. The motor provides up to half the effort, but more regular use means more exercise for the rider.

4. No Sweat!
Sweat may not be a serious issue when youre out for a leisure ride, but its more important if youre cycling to work. Although some employers are rather grudgingly providing showers and other facilities for cyclists, the great majority have no intention of doing so. An electric bike eliminates the problem at source. In hot weather, its possible to maintain a normal schedule by transferring a bit more load to the electric motor. In colder weather - or if you feel in need of exercise - just throttle back, or turn the motor off.

5. Clean & Green

Electric bikes obviously consume energy, where a conventional bikes does not (provided we ignore the environmental cost of growing and processing food - see below). However, the amount of energy used is very small compared to a moped, motorcycle or car. Besides fuel, the only consumables are the batteries, and these can normally be recycled when life-expired. As for energy use, electric bikes typically consume fuel at an average rate of 100 to 150 watts of electrical energy, against 15,000 or so for a car (admittedly travelling much faster). In terms of fuel consumption, an electric bike achieves about 800-2,000mpg (290 - 700 litres/kilometre) (d). No other commercially available vehicle can match figures of this kind.

If its hard to place these numbers in your own lifestyle, think of a 100 watt electric light bulb burning for an evening - thats enough energy to propel an electrically-assisted bike for 20 to 40 miles...

6. Genuinely Sustainable
Theres a lot of nonsense talked about sustainability in transport, but an electric bicycle can be made genuinely sustainable. Purchase electricity from a green supplier, or generate your own with a roof-mounted windmill or solar panel array (see Solar Power facts), and the vehicles fossil fuel consumption will be zero. Surely a conventional bike does that already? Only if you grow the food you consume whilst riding it. Unfortunately, most modern food production and distribution is so fuel-intensive that the consumption of a typical cyclist is not terribly good.

7. Faster travel
In theory a car can average a high speed, but in practise speed often falls below 10mph in cities. The problem is congestion - motorcycles get around this to some extent, but theyre still confined to the road network. An electric bike can maintain a higher average speed than a bicycle but take advantage of the same network of cycle facilities, giving access to routes that cars and motorcycles cannot reach. The result is often a faster door-to-door journey time than any other mode. And by taking advantage of the uncongested cycle network, but eliminating hills and headwinds, electric bikes are often the most consistent mode of travel.

8. High Resale Value
Electric bikes are new technology, and its early days yet, but the evidence points to a much better resale value than a conventional bike. True, a typical electric bike costs more to buy, at 400-1,000, but it seems youll get most of that back if you sell the machine on.

9. Motorised, but no Red Tape!
You know how it is... MOT due, log book missing, insurance costs rising year on year. Electric bikes are treated just like ordinary bicycles for legislative purposes, so theres absolutely no registration or legislation to worry about. You are of course free to insure the machine if you wish, but theres no compulsion to do anything but enjoy yourself!

How e-bikes work is by assisting your pedaling. Electric bikes are everyday bicycles with an added battery-powered electric motor. Although capable of pushing you along without your help, electric bikes perform noticeably better when you pedal. The average "couch potato" who normally rides at 10 mph can ride at 15-20 mph using the same effort. He can also expect a range of 10 miles, with a recharge time of several hours. Do you remember that easy pedaling after you get your bike up to speed? Thats the cruising feeling you get all the time with an electric bike.
Power, when activated by a throttle on the handlebar (power-on-demand) or in response to your pedaling (ped-elec), gives you an immediate, nearly silent push. When you release the throttle (or stop pedaling), the motor coasts or "freewheels" - like when you stop pedaling a regular bike. Standard bicycle hand brakes and gearing round out the controls.
"Power-on-demand" means just that - no pedaling required! Although all electric (or "electric-assist") bikes are designed to work with your pedaling, power-on-demand allows you to break the rule. Most systems offer a variable speed control, although some are simply on/off (like the yellow switch pictured). A "ped-elec" wont deliver motor power unless it senses you are pedaling. And its "power output to pedal pressure" ratio is often adjustable. Most people find 400-watt motors adequate for their needs, although folks with steep hills may want more power. Some bikes offer through-the-gearing power assist - i.e. the force of the motor goes through the bikes gearing system - which provides better hill-climbing and top-end speed than direct drive systems with motors of the same wattage rating.
Electric bikes come in two basic designs - adaptive and purpose-built. The adaptive type starts with a bicycle and adds a drive system to it. A purpose-built e-bike is designed from the ground up. Adaptives are less expensive, less stylish, and may require installation (allow 3 hours if youre familiar with tools; otherwise your local bikeshop mechanic will charge about $75). Purpose-builts generate interesting designs and features (like brake-activated tail lights). Users of both types enjoy easy acceleration, hill climbing, and cutting through headwinds. Rechargeable batteries, usually sealed lead-acid, provide power for the electric drive motors. Charging costs less than 5¢ of electricity from common 110 VAC wall outlets. Charging times vary widely due to charger output and battery capacity, but you can expect to recharge in less than 8 hours with most stock chargers. Quick chargers are available.
Mopeds differ from e-bikes in that they generate more speed, risk, range, expense, pollution, and legal issues. Top speed of mopeds is limited by law to 30 mph. Often, a drivers license and registration is required. An electric bike, which by law is limited to a top speed of 20 mph, reduces the risk of serious injury. Its shorter range of 8-20 miles is plenty for errands and short commutes. E-bikes are the cleanest motorized vehicles - both in terms of air pollution and noise. If you own a bike, you can motorize it for as little as $500. Or buy a purpose-built e-bike for up to $3000. Either way, you can ride your e-bike without a drivers license, vehicle registration, or insurance.

Electric bikes perform depends on many factors. The most important factors are listed here with the (generally speaking) most important at the top:

battery capacity (measured in volt-amp-hours)
terrain (number and incline of hills)
e-bike speed (range at 10 mph is 8 times as far as at 20 mph)
wind conditions (going 10 mph against a 10 mph headwind feels like 20 mph to the bike)
pulling a trailer (which is like pulling another bicycle)
correct tire inflation (under-inflated tires slow you down)
weight of rider and baggage
motor/controller/drive system efficiency

As you can see, battery size ranks at the top. With a pair of big car batteries mounted on a trailer, you can go for hours. To double your range, double the size of your battery pack. Many, if not most, e-bikes come with two 12-volt 12Amp-Hour batteries which will take an average rider 8, to maybe 10, miles over moderate terrain. System efficiency ranks at the bottom because most systems are 85% to 95% efficient. The speed you go makes a big difference in how far you go.
All else being equal, range is a function of either:
1) battery capacity (amp-hours X volts) or 2) speed and ease of recharging (high-power chargers provide lots of miles in less than one hour). There is a direct relationship between battery capacity (amp-hrs) and both weight and physical size (total volume). Commonly used sealed lead-acid batteries weigh twice as much a NiMh batteries of the same rating and four time a Lithium Polymer battery. For hill-climbing, expect about 3 feet of elevation gain for every volt-amp-hour. For example, a stock battery pack (two 24-volt, 12 amp-hour batteries) will take you up about 800 feet without pedaling (3 feet X (24 X 12) = 864 feet). Another way to compare performance is the ability to gain elevation.
All else being equal, speed is a function of motor (watt rating) and controller. Most electric bike motors are capable of higher performance characteristics than the controller allows.
[Beware: Some e-bike advertising touts their high-power motors (e.g. 600 watts), but only deliver 400 watts through the controller.]
As for power, consider that Lance Armstrongs average speed over a 2-hour ride is 20.5 mph. Thats just over the legal speed of e-bikes. Lance expended about 1/2 horsepower, or 373 watts, continuously. Most e-bike motors operate continuously in the range of 300 - 600 watts. Most e-bikes, therefore, will make a "Lance Armstrong" of difference in getting you down the road and up the hill!
Regenerative braking doesnt yield much "juice" back into the battery. Even the hi-tech regen on electric automobiles gains less than 10% of the original charge. Therefore, given a choice of either regen or freewheeling, you will generaly get more range with freewheeling - unless you have a hilly route.
Due to the nature of batteries, you can double the battery life expectancy by discharging only 50% of capacity instead of 75%; you get 6 times the battery life at 30% capacity usage per cycle. Think of battery lifetime as having $1000 in the bank and withdrawing a dollar with each 30% disharge cycle -- and withdrawing $10 every time you deeply (85%) discharge the battery.
Rules of Thumb:

Get a battery pack that goes at least twice the range you usually expect to ride.
Range is proportional to battery size; twice the battery size = twice the range.
When speed increases, range decreases even faster; 1/3 faster = 1/2 the range.
A 400-watt motor takes an average rider up all but the steepest hills (but weak controllers can limit performance).
Two 12-volt, 12 amp-hour batteries will take an average rider 10 miles at 15 mph or up a hill thats 800 feet tall.