This electronics guide should clear up at least some of the headaches that occur when buying and wiring your electric skateboard parts.
Contents: (Click to jump)
1. The Electrical Components
Please read the separate parts pages for finer details about the components. Here we will only brush the surface for context for later on in the page.
The Motor is the powerhouse of your board turning electrical energy into mechanical energy. As you will inevitably be riding your skateboard, the motor needs to be powerful enough to move your weight + the board’s weight.
To be able to move this weight your motor needs to have relatively high torque, ideally the more torque the better. Bigger motors generally have more torque (more electrical windings and stronger magnetism) but add more weight. The second important factor is the Kv rating, which is just a number indicating the revolutions per minute per volt with no load.
Read more details about the motor.
The batteries are the fuel of your board, storing and releasing electrical energy when needed.
You need to get an idea of the motor as well as your batteries before you buy either one. This is so you know the details of the voltage and current your system can take. This will be discussed in more detail later.
Two other important factors when choosing your battery or batteries are the capacity and the C-rating. Obviously, you are going to want a high capacity so you can travel further between charges, but a larger capacity adds weight.
Read more details about the batteries.
The speed controller is the brain of your board, managing the varied speed of the motor from the wireless throttle.
An electronic speed controller (ESC) is required so you can speed up and slow down. Benjamin Vedder designed an ESC called the VESC for electric skateboards and is highly recommended.
Read more details on speed controllers.
2. Electrical Parameters
You may well have read or heard talk of volts, amps, and watts. Well, they are electrical characteristics which are important for explaining electrical potential, flow, and power.
|Voltage||Volts (V)||A measure of electrical potential difference||Wiki|
|Current||Amps (A)||The flow of an electrical charge||Wiki|
|Power||Watts (W)||A unit of power||Wiki|
Why are they important? Changing these parameters can affect your electric skateboard’s performance. This means you have to carefully choose your components to fit each other and in turn achieve the performance you want. Careless overpowering, however, can destroy your components.
Volts will be affected by your batteries and will affect your motor. You can control the amount of voltage in your system by connecting cells or batteries in series. For example, connecting two 18.5V batteries in series will cause the system to run at 37V. The motor (and speed controller) will have a maximum volt rating which must not be exceeded. Running an electrical motor at too high or too low volts will cause damage. However, the higher the voltage the faster the speed of the motor. Running just under the upper volt parameter is generally best.
Current is the flow of electrical charge and is controlled by changing the voltage or resistance in the circuit (see Ohms’ Law). It’s a lot harder to regulate the amps in a system than it is voltage, but you can check the current using an ammeter. The current must not exceed your components’ specifications though, otherwise, it could damage them.
Some more parameters you might come across:
|Motor Velocity Constant||Kv||RPM per volt of an unloaded motor||Wiki|
|Milliampere Hour||mAh||A unit of electrical charge||Wiki|
|Charge/Discharge Rate||C||Measure of the speed at which a battery can charge or discharge||Wiki|
|Revolutions per Minute||RPM||Number of turns in one minute||Wiki|
3. Wiring Diagrams
Once you have the parts for you electric skateboard, you need to connect them all. The best way to see this is in wiring diagrams. There are many variations of e-boards, and so your board may be slightly different, but the following diagrams should be of use.
Basic E-Board Wiring
Above shows how a basic electronic skateboard is wired. It could be even simpler if you take out the battery percent indicator and switch, and would just have the battery connecting to the VESC and the VESC connecting to the motor.
BMS E-Board Wiring
Above is a wiring diagram for e-boards using a BMS (Battery Management System). In this instance, the BMS is being used to discharge the batteries as well as charge them so it would need to be able to handle the current and voltage the VESC and motor draw from the battery (which can be quite high on electric skateboards). Remember to check the specifications of your BMS and other components.
BMS Wiring for Charging Only
The above diagram bypasses the P- part of the BMS, meaning the battery discharge doesn’t ever travel through the BMS. The wire that would normally go from the P- to the VESC, now goes from the battery itself. This way your BMS doesn’t need to have such a highly rated amp and volt protection which is cheaper. It only needs to be rated enough to handle charging. The rest of the diagram is the same.
How you charge your board depends on whether you have a BMS or not. When you charge your batteries, each cell in that battery needs to be balance charged in order to maximize the capacity of each cell, and in turn the battery overall. Balance discharging does the same thing but for when you are using your battery. This will both increase the capacity of charge in your battery and the lifetime of the battery.
A Battery Management System (Wiki) manages the charge and discharge of your batteries along with other safeguarding measures to protect your battery and hopefully make it last longer. You can choose to install one on your e-board and will affect how you charge your batteries.
Charging without a BMS
If you do not have a BMS, you will need a balance charger to charge your batteries. It has connectors for both the positive and negative wires as well as the balance wires. When it charges it will use the information from the balance wires to balance charge your batteries. Many balance chargers are compatible with multiple battery variations, e.g. Li-Po, Li-Ion/3S, 4S, 5S/XT-90, Bullet connectors.
While this seems the simplest option, there are some drawbacks.
- If you have two or more batteries connected in your board, you will need to charge each one individually
- There is no balance discharge
- You have to unplug the batteries from the circuit every time
This is why some people invest in a BMS for their board.
Charging with a BMS
Installing a BMS is initially more complicated to set up because of the extra wiring, but it makes charging and discharging your batteries easier and safer. You will not need a balance charger if you have a BMS as it will do the balancing itself. All that is needed is a standard brick charger like you would find with a laptop and a compatible charging port to connect the brick charger to the circuit.
Essentially, after installing the BMS it is a case of plugging in and charging – the BMS will take care of the rest.
- More wiring which can be complicated
- Making sure the BMS is compatible with your batteries and system