Troubleshooting - Electric Drive System

Motor Controller Outputs

The battery pack feeds directly into the motor controller where the power is split into two (2) outputs. Obviously the main 50v output is used to feed the drive motor, but there is also 5v output that is used to power the LCD display. If the LCD display is not operating, there's a good chance the problem may lie with the controller's 5v output.

  • Is the LCD Display working?
No - (Abnormal) Click Here
Yes - (Normal) Continue


Tools of the Trade

Motor/Controller Tester

Once you've ruled out the battery pack as the problem, and the LCD Display appears to be operating properly, you're really only left with the motor or the controller.

An issue with the motor, controller, or motor-to-controller connection can appear to be mechanical in nature. Testing is always best done with the motor unloaded, spinning freely.

In order to troubleshoot the motor controller and motor, every e-cruiser we sell includes a very handy Motor/Controller Tester intended for troubleshooting your e-bike motor and controller.

If you're a shop technician working on one of our e-cruisers, ask your customer for this tester. They're also available in our parts shop for around $30.

Motor & Controller Overview

In order to troubleshoot the motor/controller, you must first have a fundamental knowledge of how a brushless DC motor operates.

This video that does a great job of visually explaining how a 3-phase brushless motor works. The example motor used is a small computer fan, but essentially it is the same concept as the rear hub on your electric bike.

We're not looking to make you an expert on motors, but rather just familiar with the concept and the relationship between motor windings and hall effect sensors (for proper timing).



Troubleshooting the Motor-to-Controller Connection

While the video above didn't dive too deep into how the controller actually works, you only need to grasp the concept of its relationship to the motor.

The first test is to see if the controller output voltages and signals are operating correctly.

As stated previously, the cables shown in this simplified diagram have multiple conductors. You can take a closer look at this connection on the schematic wiring diagram.

Important Note: The small Hall Sensor wires are quite delicate and the pins in the plugs can back out. If that happens, the smooth timing sequence on the motor is thrown off and can feel like a mechanical issue.

A poor connection between the motor and controller is the most common cause of intermittent, poor, or non-function issues.

Connect the Tester to the Controller

The right half of the Testor is for checking the motor controller's output.

The motor controller has two cable assemblies that connect it to the motor. One cable assembly is the thicker gauge Phase Wires (Yel/Grn/Blu). The other smaller gauge cable is the Hall Sensor Wires.

In order to perform the test, the motor-to-controller cable assemblies will need to be disconnected.

⚠️  Turn OFF the electric drive system (main power switch).

Connect the Tester to the motor controller output cable assemblies.


Test the Controller

The Tester performs two different functions. The right half of the tester is for testing the controller while the left half is for testing the motor. The Tester does have an internal 9v battery, but that is only used when testing the motor. This first test will check to make sure the motor controller is putting out the correct voltage and Hall Sensor timing sequences.

⚠️  Turn ON the main power switch to power up the controller.

✔︎  The smaller LED in the center of the Controller Tester should flash, indicating 5v power is present for the Hall Sensors.

✔︎  Press the throttle half way and the six indicator LED's (circular pattern) should flash two by two in sequential order.

  • Does the motor controller appear to be triggering the LED's properly?
Yes - (Normal) Click Here
No - (Abnormal) Replace Controller

If it doesn't flash two LED's at the same time, rotating in a pattern, then the motor controller is not functioning correctly and should be replaced. A replacement motor controller is available in our parts shop.