This is your first e-bike build. You did everything as instructed, connected all the wiring properly, and matched up every color on the phase and hall wires… So why is the motor running backwards when you apply the throttle?
It comes down to a simple fact from the reality of e-bike builds: In practice, controllers and motors rarely match the way they should on theory. As a friend of mine likes to say, “If everything works from the first time you plug it in, you’re either really lucky or you did something terribly wrong.”
Here’s the thing: If you buy a pre-configured kit, you simply put everything together and you’re all set to go. But if you buy the motor and controller separately, the phase and hall wiring scheme rarely matches up.
As a result, you have to play around with the wiring until the wheel’s rolling in the right direction (and it does so smoothly).
How to Reverse the Rolling Direction of the Wheel
Nine times out of ten, the mismatch is in the phase wires. But, sometimes, it can also be in the hall wires.
It’s like picking a lock or fiddling with an unknown gadget in an escape room: When you don’t know the right combination, you have to play around with all of them until you find the one that opens the door.
As explained on the Spintend blog, there are 6 combinations to test for the phase wires, and each phase combination has another 6 possible hall combinations. This is a total of 36 combinations that you may need to test.
The way to fix this depends on the type of controller your e-bike is fitted with. When it comes to the rolling direction of the wheel, there are two types of e-bike controllers: those with a self-learning module, and those without.
With a Self-Learning Module
The self-learning module is a pair of white wires, called learning wires or self-learning wires, or sometimes reverse wires, which let you program the controller to spin the wheel in the right direction without fiddling around with the phase and the hull wiring.
When you power on the system and connect these two wires together, you’ll reverse whatever direction of spinning is programmed into the controller. Then, when you disconnect the wires, the controller will remember that direction.
It goes like this:
- Power on the system.
- Connect the self-learning cables.
- Apply the throttle and check the spinning direction.
- Disconnect the cable.
- Power off.
If the wheel spun in the right direction, you’re pretty much done. The e-bike controller will remember it. If it spun in reverse, repeat the steps above so you get to the correct movement and memorize it into the controller.
The folks from Canadian scooter dealer Ride the Wind Ebikes explain how the self-learning module works in the YouTube video below:
Without a Self-Learning Module
If your controller doesn’t have a self-learning module, you’ll have to test the combinations manually.
Always start with the phase wires. Not only are they fewer (3 wires, 6 combinations), but they’re usually what solves the problem. The hall wires should be your second resort in case no combination of phase wires worked well.
Write down the combinations you’ve tested in a notebook or on a piece of paper so you don’t do redundant work.
You can see this explained in a video on the karma-Ebikes YouTube channel: