Let's not pretend that you don't know what some people think about electric bikes. Now let's ignore those people completely.
If you want to make it easier to ride uphill or against the wind; if you want to be able to ride faster and longer; if you want to avoid traffic when commuting to work; if you want to enjoy a group ride without straining to keep up, then an electric bike could be for you.
Many people would like to cycle more, to work, on day-to-day errands, if only... An electric bike removes "if only" barriers. With an electric bike, you can arrive at work not covered in sweat, and not have to change clothes or shower at work. You can carry heavy loads, such as groceries, without additional strain. It is not unusual for the owner of an electric bike to get more exercise, because they use their car for fewer (or none) of the short-range trips that previously seemed to be too much trouble to do on a bike.
Electric bikes also make cycling more available to people who may have disabilities, fitness issues or motivational issues that make cycling seem too challenging.
Because of the weight of the battery and motor, you can expect an electric bike to about double the weight of a typical bike -- to around 50 or 60 pounds. The less expensive the battery technology, the more weight the battery will add. (See below.)
In the US, electric bikes will assist you up to 20 mph. Above 20 mph, it's all you and/or gravity. The range is typically from 20 to 25 miles on a fully-charged battery. A lot depends on the factors independent of the technology, such as the weight of the rider, the weight of the cargo, the terrain, the amount of pedaling the rider does, and even the outside temperature.
Typically, electric bikes range in price from $500 to $4000. The lower end of that range, however, is usually not a good investment. It takes good components to make a good bike, and it takes good technology to make an electric bike pay off. A rider who uses an electric bike on short trips and errands instead of driving a car, will be paid back quickly in money saved on gas, repair and maintenance (oil changes, tune-ups, tires, etc.). Charging an electric-bike battery generally costs less than 20 cents worth of electricity (based on average US costs per kWh).
Electric Bike Features
- Throttle: With many electric bikes, the rider controls the power with a handlegrip throttle, as on a motorcycle. The more power wanted from the motor, the more the rider twists the throttle. Pedaling is not strictly necessary, although most throttle-controlled e-bikes are unsatisfying scooters. (Just as scooters are unsatisfying bikes.) One advantage of a throttle controlled electric bike is the ability to jump more quickly from a dead stop, say, at a traffic light, as opposed to the slight lag associated with...
- Pedal Assist (a.k.a. pedelec): On electric bikes with pedal assist, no power is delivered to the motor unless the rider is pedaling. The motor delivers power to the drive train proportional to amount of effort provided by the rider. For example, the Bionx system used in Ohm Electric Bikes, can detect the power from the rider, and respond with 35, 75, 150, or 300% of that power. Some bikes have both pedal assist and a throttle. Pedal assist electric bikes are less suitable for people with medical conditions who need the option of not pedaling, or for people who just sometimes don't want to pedal.
- Regeneration: Some bikes allow the rider to return energy to the battery with a "training mode" or when braking. This is called regeneration, as in "regenerative braking." Rather than using friction to slow down the bike (as with regular brakes), the motor turns into a generator and the rider's effort or momentum is what powers the generator. However, regeneration doesn't amount to much recharging of the battery. A rider expecting to fully -- or even noticably -- recharge the battery in this mode will have to ride a long, long, way. However, regeneration can be used to an advantage on long or steep hills to moderate speed while extending the battery range just slightly.
- Off-Bike Charging: Most electric bikes are charged by connecting the battery to the charger while the battery is still connected to the bike. For some users, it may not be possible to charge the battery in the place where the bike is parked. In these cases, the battery must be removed from the bike and charged elsewhere. Not all electric bikes make this easy. For aesthetic reasons, some batteries are cleverly hidden in the bike's down tube, making it necessary to turn the bike upside down before removing the battery. Other bikes are designed to make battery removal quick and easy, such as bikes by Kalkhoff, and Ohm, so the battery can be charged elsewhere.
- Rear-Wheel Drive, Front-Wheel Drive, and Crank Drive: The location of the motor on electric bikes make a difference. Rear-wheel drive delivers power directly to the rear hub, which usually (but not always) favors a cogset, and crowds out the possibility of an internal rear hub. When the motor is located in the front wheel, the bike becomes a two-wheel drive, and allows for an internal rear hub or a cogset. Since electric motors operate more efficiently at higher RPMs, both front- and rear-wheel motors cause the motor to operate at less than full efficiency at low speeds, which drains the battery more quickly. Crank Drive motors deliver power to the bikes crank, which allows the motor to operate at the cadence of the rider rather than at wheel speed. The result is generally higher RPMs and greater efficiency of the motor.
- Battery Types: Each type of battery comes with its own care requirements. Like houseplants, what will harm one is just the right thing for another. Battery technology is often measured in an energy-to-weight ratio -- watt-hours per kilogram or Wh/kg -- the ideal being a light battery with lots of energy. Naturally, the batteries with the higher Wh/kg ratio are the most expensive and the least green. Lead-Acid batteries have about 25 Wh/kg, and they charge slowly, but they are low cost and recyclable. Nickel-Cadmium batteries have 50 Wh/kg, charge quickly, and can take a deep discharge without harm. Nickel-Metal Hydride batteries, with 70 Wh/kg, last a long time before needing replacing, but a full discharge is harmful to the batteries, and they require "intelligent charging" from the battery charger. Lithium-ion are the lightweight champs, with up to 150 Wh/kg; they charge quickly, but don't last for as many charge cycles as other battery technologies, aren't usually recyclable, and are fussy about how they are recharged (they require a complex battery management system). All of the electric bikes sold on Bike Tech Shop come with the appropriate charging system to maximize the life of the battery. A rider who replaces car trips with an electric bike, is already greener no matter which battery technology he/she chooses.
At Bike Tech Shop, we are big fans of the book Electric Bicycles
by David Henshaw and Richard Peace. Our pal Pete Prebus runs Electric Bike Report
, reviewing electric bikes, and industry trends.
A2B Electric Bikes: The A2B line of electric bikes is brought to you by Ultra Motor, one of the world's leading developers of Light Electric Vehicles.
Hebb Electric Bikes: The Hebb line of bikes combines more than 35 years of expertise in fitness and electric-powered lifestyle equipment.
Ohm Electric Bikes: Ohm electric-assist bicycles offer a responsive and powerful ride, with premium components for performance, comfort and convenience.