Welcome to Electric-Bikes.com

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

1. battery capacity (measured in volt-amp-hours)
   
2. terrain (number and incline of hills)
   
3. e-bike speed (range at 10 mph is 8 times as far as at 20 mph)
   
4. wind conditions (going 10 mph against a 10 mph headwind feels like 20 mph to the bike)
   
5. pulling a trailer (which is like pulling another bicycle)
   
6. correct tire inflation (under-inflated tires slow you down)
   
7. weight of rider and baggage
   
8. 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. Here are some anecdotal estimates:

• ZAP DX system with 13-lb battery can gain about 450 feet of elevation.
  
• Currie U.S. ProDrive system with 20-lb battery can gain about 800 feet of elevation.
  
• Betterbike Model 20 with two 20-lb batteries can gain about 1600 feet of elevation.
  
• EV Global 36-volt bike with 20-lb battery can gain about 800 feet of 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 Armstrong's average speed over a 2-hour ride is 20.5 mph. That's 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 doesn't 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.
  
• For every two miles you go, plan on about one hour of charging and about one cent of electricity.
  
• 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 that's 800 feet tall.

"Bargain Buys" Most electric bikes priced less than $500 at big box retailers and on-line are aimed at the kid/teen/toy market. They generally lack the performance and durability that people want and expect. Also, parts and service can be problematic with both big box retailers and on-line vendors. We urge you to invest in an e-bike that will serve you (and others) for many years. If you choose to buy a "Bargain" anyway, read our quality control and final adjustment guidelines. Remember, if it's poorly constructed and you can't get repair parts, it's likely to become land-fill material.

Diagnose and fix e-bikes.

First off, distinguish between the bicycle and the electric drive system. If you're having problems with a bike part, your local bike shop can help. Or you can find lots of useful fix-it information at:

• Sheldon Brown's website: http://www.sheldonbrown.com/harris/bikes.html
  
• Or get Bicycling Magazine's manual at: www.bicycling.com
  
• Or get an interactive repair CD from www.bfr-it.com (1-866-237-2453 toll free)

• start with our diagnostics page
  
• research the available documentation
  
• find a repair shop or somewhere to buy parts
  
• search the archives of the online power-assist group

If you start with our diagnostics page and successfully isolate your problem, you'll know whether you can fix it yourself or want a service company to fix it. To fix it yourself, get parts from a parts retailer.

Building e-bikes (D-I-Y).

Do-It-Yourselfers may want to consider a set of plans for the Slipstream Electric Bike. Others will want to delve into motors, controllers, batteries and gearing at our D-I-Y introduction. Then check out the online users group, especially the archives which are searchable for your keyword interests. Also helpful is the book Electric Bicycles: A Guide to Design and Use, William C. Morchin, Henry Oman, ISBN: 0-471-67419-2, Paperback, 190 pages, November 2005, Wiley-IEEE Press, $39.95, http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471674192,miniSiteCd-IEEE.html

Resources for riding (trailers, how-to, etc.)

Buying a bike.

Fixing a bike.

Commuting by bike.

Learning to ride a bike.

• Articles for beginner cyclists: http://sheldonbrown.com/beginners
  
• "How to Not Get Hit by Cars" by Michael Bluejay

BICYCLE OPTIONS: trailers, tandems, technologies, and access