eBike Basics

Motor

The heart of the drive. The motors kV determines the speed and torque possible from your battery voltage. It’s mass dictates how much power it can safely handle. It’s construction will dictate it’s longevity.

Batteries

We recommend 5s or 6s LiPo. This gives us some of the best power/energy density batteries on the planet, that are cheap, easy to build, easy to charge, easy to expand, but does take some special care and precautions.

Speed Controller

The speed controller has the job of turning the batteries DC voltage into a clean signal that turns the motor. By using ESC (Electronic Speed Controllers) typically found in remote controlled aircraft, we have some of the lightest and smallest packages with proven robustness, but the particular application to an ebike requires us to ensure we do not run them at low speed and high power.

Throttle

The ESC typically requires a servo tester to send a PWM signal of the correct type to the ESC to drive the motor. For an ebike we need something a little different, to take the specific ergonomics of a bike into account. The options currently in use for the Commuter Booster are:

Hall Throttle

With a simple modification to a servo tester a standard ebike hall effect throttle can be made to work with the RC ESCs.

Pot Throttle

A simple replacement of the potentiometer in the servo tester with a potentiometer style throttle, like a Magura, allows their use.

Button Throttle

For road bike bars the twist throttles are not suitable. And so was born the button throttle, in a simple on/off mode of operation.

Extras

Ramp Control

To finely control the engagement and disengagement of the motor with the tire it is important to control the rate at which the motor accelerates.

Current Limiting

Current limiting controls the maximum torque the drive can apply, which is important to maximise efficiency, and reduce tire wear. It also limits the maximum power of the drive which can help limit the maximum assist, giving you more of a work out, reducing the stress on the motor, increasing your range, and help you stay faithful to local laws.

Minimum Speed

To minimise the Commuter Boosters size and weight while maximising performance, compromises had to be made. The main one being that the drive is not designed to be used at low speeds, and high loads. The motor and ESC are just not designed to be operated in this manner, and likely to die a premature death. To avoid this situation the user must either be mindful of this during use, or a throttle override must be implemented that zeros the throttle signal unless a minimum speed is exceeded. This device is currently under developement.