With most e-bikes, you use the battery to provide extra power, and then recharge it after your trip. Going downhill provides enough speed to recharge a bike with a self-charging mode, but you would need to go downhill for about 200 miles to fully recharge the battery, according to NYCeWheels.com.
The range of an e-bike depends on the size of the batteries. Most will allow you to ride 10 to 20 miles on a single charge. If you pedal for part of the trip, you can go about 15 to 30 miles per charge, according to Eco-Wheelz.com. You can use the motor of an e-bike all the time, use it just when you need extra power, or turn it off and pedal it just like a normal bike.
Charging a battery normally takes from two to six hours, depending on the manufacturer and the battery type. Higher quality batteries will take less time. Each full charge costs 10 cents. This means it costs less than a penny a mile to operate an e-bike, according to Eco-Wheelz.com. That makes it very energy-efficient, even if you must plug it into an outlet instead of pedaling.