Controllers for brushless motors: E-bikes require high initial torque and therefore models that use brushless motors typically have Hall sensor commutation for speed and angle measurement. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. The controllers generally allow input by means of potentiometer or Hall Effect twist grip (or thumb-operated lever throttle), closed-loop speed control for precise speed regulation, protection logic for over-voltage, over-current and thermal protection. Bikes with a pedal assist function typically have a disc on the crank shaft featuring a ring of magnets coupled with a Hall sensor giving rise to a series of pulses, the frequency of which is proportional to pedaling speed. The controller uses pulse width modulation to regulate the power to the motor. Sometimes support is provided for regenerative braking but infrequent braking and the low mass of bicycles limits recovered energy. An implementation is described in an application note for a 200 W, 24 V Brushless DC (BLDC) motor.
It will be of little surprise to learn that the Hanebrink all-terrain vehicle was designed by six time Mountain Bike national class champion and former U.S. National Team member Dan Hanebrink. It's based on 1993's Extreme Terrain fat tire pedal bike and is made to order at the Fortune Hanebrink workshop at Big Bear Lake, California. Echoing the philosophy of many electric assist bicycle makers, Hanebrink says: "We are not trying to replace standard bicycles, we want to replace cars and trucks."
And let’s not forget the economic advantages of owning an e-bike. The annual cost of running a new family car is, on average, about $9,000 per year. Running an electric bike costs around $400 per year. And while filling a gas tank costs around $30, recharging an electric bike battery costs only about 50 cents. A tank of gas may get you further, but not 60 times further!
Electric bikes are here in a big way. Liberated from some of the normal constraints of standard bike design like weight and gearing, e-bike design has exploded; if you can imagine it, someone has built it. From cargo bikes to city bikes, messenger bikes to mountain bikes, road bikes, and even beach cruisers, there is something for everyone. The beauty of e-bikes is they make the joy of cycling accessible to so many people in so many ways.