Robert A. Bériault's Books & eBikes
BEFORE YOU BUY AN EBIKE
Motors vary in power from 250 watts (W) to 500 W in Canada and up to 750 W in the United States, and from 24 volts (V) to 48 V. Batteries act as the bicycle’s gas tank. They vary in capacity from 6 ampere-hours (Ah) to 16 Ah. My Pedego has a 48V 400W motor and a 15 Ah battery, which gives 720 watt-hours (Wh), a good combination of power and range. To calculate Wh, multiply voltage by amperage. Mountain bikes can have motors as powerful as 2000 watts, but these are strictly for off-road use and don’t usually offer a lot of range.
The battery can be placed either on the rear baggage rack, in the seat tube or the (front) down tube. Having that extra weight on the top rear part of the bike makes it unstable when parking or walking the bike, because of the high centre of gravity. Ideally, it should be placed on the seat or down tubes, for a lower centre of gravity and better stability. The most elegant configuration is where the battery is incorporated into the down tube and is completely invisible.
Whereas cars are now almost all front-end drive, there is no such consensus when it comes to where to put the motor on an electric bike. The most common configuration is the motor in the hub of the rear wheel, which results in direct drive. Changing gears has no effect on the motor. The advantage of this system is its simplicity and low cost. If something goes wrong with the motor, you just need to replace the rear wheel, which you can do yourself if you know how to fix a flat. The next configuration of drive, in order of popularity, is the mid-drive system, where the motor is incorporated into the bicycle’s pedal crank. The advantage of this system is its great ability in hill climbing, because the motor benefits from the same gear as the cyclist does. Because the motor doesn’t strain as much, it will likely last longer. However, repairs could be more costly. The least popular configuration is having the motor in the hub of the front wheel. If you are using the bike in the city for normal use, the lower traction they provide in steep, slippery hills would not be a concern.
The bicycle’s computer:
This is the ebike’s control centre. The computer, or controller, located on the handle bars, allows you to select the amount of assistance you want from the motor. Typically, the controller allows you to choose from three to five levels of assistance, depending on the model.