Summary of AN OPEN-SOURCE EBIKE MOTOR CONTROLLER
Summary: An open-source VESC-based motor controller was adapted to replace the proprietary controller in an Ampler Curt stealthy ebike. The custom controller runs on a small Arduino housed in the downtube, preserves the bike’s clean look, reaches about 35 kph, and uses pedal-backspin to toggle lights and change assist levels. Torque-sensor pedal support is not yet implemented, but the project demonstrates recovery and longevity potential for proprietary ebikes.
Parts used in theDIY VESC-based controller project for Ampler Curt:
- Ampler Curt ebike (stock frame and components)
- 36 V, 350 W rear hub motor (stock)
- Proprietary battery (stock)
- VESC-based open-source motor controller
- Arduino (tiny unit installed in downtube)
- Wiring and connectors to integrate controller, motor, battery, and sensors
- Pedal sensors (stock torque-sensing pedals are present but not yet supported)
- Lights integrated with controller
DIY e-bikes are often easy to spot. If they’re not built out of something insane like an old washing machine motor, the more subtle kits that are generally used still stand out when compared to a non-assisted bike. The motors tend to be hub- or mid-drive systems with visible wires leading to a bulky battery, all of which stand out when you know what to look for. To get a stealthy ebike that looks basically the same as a standard bicycle is only possible with proprietary name-brand solutions that don’t lend themselves to owner repair or modification, but this one has at least been adapted for use with an open source motor controller.
The bike in use here is a model called the Curt from Estonian ebike builder Ampler, which is notable in that it looks indistinguishable from a regular bicycle with the exception of the small 36-volt, 350-watt hub motor somewhat hidden in the rear wheel. [BB8] decided based on no reason in particular to replace the proprietary motor controller with one based on VESC, an open-source electric motor controller for all kinds of motors even beyond ebikes. Installed on a tiny Arduino, it fits inside the bike’s downtube to keep the stealthy look and can get the bike comfortably up to around 35 kph. It’s also been programmed to turn on the bike’s lights if the pedals are spun backwards, and this method is also used to change the pedal assist level, meaning less buttons and other user-interface devices on the handlebars.
[BB8] has been working on this for a while, and although the bulk of a working ebike controller is there, it still doesn’t support the torque sensing pedals included with this bike. We’re presuming that this is still a work-in-progress as the Arduino and associated code easily interfaces with all the other sensors available on this bike. Hopefully this open-source motor controller finds its way into other proprietary systems as well, since a lot of these ebikes can turn into massive paperweights if the companies who originally built them go out of business or simply decide to stop supporting older models. Of course, you can avoid this issue entirely by building your own ebike from spare parts.Source: AN OPEN-SOURCE EBIKE MOTOR CONTROLLER
- What was replaced on the Ampler Curt ebike?
The proprietary motor controller was replaced with a VESC-based open-source motor controller running on an Arduino. - Can the custom controller keep the bike looking stealthy?
Yes, the Arduino-based controller is installed inside the downtube to preserve the bike's clean, standard-bicycle appearance. - How fast can the bike go with the new controller?
With the VESC-based controller the bike can comfortably reach around 35 kph. - Does the new controller support the torque sensing pedals?
No, torque sensing pedals included with the bike are not yet supported by the custom controller. - How are lights and assist levels controlled?
The controller is programmed to turn on lights and change pedal assist level when the pedals are spun backwards. - Is the project intended to be an owner-repairable solution?
Yes, using an open-source VESC controller and Arduino aims to enable owner repair and modification compared to proprietary closed systems. - Why is an open-source controller useful for proprietary ebikes?
It can prevent proprietary ebikes from becoming unusable if the original manufacturer stops supporting older models.
