Controlling a skateboard motor via an RC remote is a popular approach for DIY electric skateboard (e-skate) projects. The core of this system involves a few key components working together:

In the context of skateboard motor ratings, Kv (often written as lowercase "kv") refers to the motor's RPM (revolutions per minute) per Volt.

It's a crucial specification that helps you determine the motor's speed and torque characteristics.

Here's a breakdown of what that means and why it's important for electric skateboards:

The Basic Formula

The relationship is simple:

Unloaded RPM = Kv × Battery Voltage

For example, if you have a:

• 190 Kv motor and a 12S battery (nominal voltage of 44.4V), the motor will spin at approximately 8,436 RPM when not under load ($190\times 44.4=8,436$).

• 140 Kv motor and the same 12S battery, the motor will spin at approximately 6,216 RPM ($140\times 44.4=6,216$).

This formula gives you a theoretical maximum speed. In reality, the loaded RPM will be lower due to factors like rider weight, hills, and wind resistance.

The Relationship Between Kv, Speed, and Torque

This is the most important concept to understand when choosing a motor for your e-skate:

• Higher Kv = Higher Top Speed, Lower Torque

  • A high-Kv motor (e.g., 220 Kv) spins faster for the same voltage. This makes it ideal for achieving high top speeds on flat terrain.

  • The trade-off is that it produces less torque, meaning it will have weaker acceleration and be less effective at climbing hills.

• Lower Kv = Lower Top Speed, Higher Torque

  • A low-Kv motor (e.g., 140 Kv) spins slower but generates more torque for the same power input.

  • This is perfect for riders who want strong acceleration, excellent hill-climbing ability, or who are running larger wheels that require more torque to turn.

Other Important Considerations

Kv is not the only factor. To get a complete picture of a motor's performance, you need to consider it alongside these other components:

• Battery Voltage (V): Higher voltage directly increases the motor's RPM (as shown in the formula above).

• Motor Size: A larger motor (e.g., 6374 vs. 5055) can handle more power (amps), which results in more torque and less heat buildup, regardless of Kv.

• Gearing: The gear ratio between the motor pulley and the wheel pulley is what translates the motor's RPM into the board's actual speed. You can use different gear ratios to fine-tune your performance. For example, a lower Kv motor can be paired with a larger motor pulley (higher gear ratio) to increase top speed.

• Wheel Size: Larger wheels also require more torque to get up to speed.

In short, the Kv rating is a crucial starting point for selecting an e-skate motor. Your choice depends on your riding style—whether you prioritize high-speed cruising or powerful acceleration and hill-climbing.

1. The Electronic Speed Controller (ESC)

• This is the "brain" of your e-skate. It's a circuit board that takes power from the battery and, based on signals from the remote, sends the correct amount of power to the motor.

• The ESC regulates acceleration, braking, and speed.

• Many DIY builders use a specific type of open-source ESC called a VESC (Vedder Electronic Speed Controller) because it's highly customizable and works with various motors and remotes.

2. The RC Remote and Receiver

• The remote (transmitter) is what you hold in your hand. It typically has a thumbwheel or a trigger to control throttle and braking.

• The receiver is a small unit that connects to your ESC. It receives the wireless signal from the remote and translates it into instructions for the ESC.

• Most e-skate remotes operate on a 2.4 GHz frequency for reliable, low-latency communication.

3. The Motor and Battery

• Motor: A brushless DC (BLDC) motor is almost always used for e-skates due to its efficiency and power.

• Battery: A high-discharge battery pack, often a lithium-ion (Li-ion) or lithium-polymer (LiPo) pack, is needed to provide the high current required by the motor.

How it all connects and works:

1. Power: The battery is connected to the ESC, providing the power source.

2. Signal: The RC receiver is plugged into a dedicated port on the ESC (often a PPM or UART port).

3. Command: You use the remote to send a wireless signal to the receiver.

4. Interpretation: The receiver interprets the signal (e.g., "full throttle forward") and sends a corresponding signal to the ESC.

5. Action: The ESC takes the signal from the receiver and controls the flow of power from the battery to the motor, making the skateboard accelerate, brake, or hold a steady speed.

Setting it up (DIY process):

1. Select Components: Choose a compatible motor, battery, ESC, and RC remote/receiver combo. VESC-based ESCs are a common choice for their versatility.

2. Physical Assembly: Mount all your components (battery, ESC, motor) securely to the skateboard deck.

3. Wiring: Carefully connect the battery to the ESC, and the ESC to the motor, following the manufacturer's diagrams.

4. Connect Remote/Receiver: Connect the receiver to the ESC. This is often done via a single cable (a PPM signal wire).

5. Configuration (VESC Tool): This is a critical step, especially for VESC-based systems.

   • Connect your ESC to a computer via USB.

   • Use the VESC Tool software to configure the settings. This includes things like motor detection (to tell the VESC what motor it's connected to), setting battery voltage limits, and calibrating the remote to the ESC.

   • You'll need to "bind" the remote and receiver together so they can communicate. The specific process varies by remote but generally involves pressing a button on both devices at the same time.

By following these steps, you can create a custom electric skateboard with precise control over your motor via an RC remote.