An electric skateboard or an e-board is simply an electric vehicle that you can use for short distance transportation. As the board is powered using electricity, there is no pollution or emission. Neither do you have to spend money on gas. You can simply charge your e-board batteries when you are not traveling on the e-board. An electric-powered board can also take you to your destination faster than a traditional board can. Besides, it is just a lot of fun to travel on an e-board. After all, you do not have to constantly kick on the ground to move forward.
The system that converts a traditional skateboard into an e-board is quite simple. Hence, you can make your own e-board at home with a little bit of research. Of course, there are branded e-boards available for sale in the market that you can purchase if you do not want to spend time and effort making your own. Regardless of the approach you take, it is important to know what parts go into making this cool new type of skateboard.
Basic block diagram of an electronic skateboard
Motor – A brushless DC motor is used for electric skateboards. Brushless motors are small in size because there is no brush in the housing. It can deliver a decent amount of power for its small size. You can choose the best motor for your skateboard by looking at the KV ratio. Every brushless DC motor will have a KV ratio associated with it. For skateboards, KV ratios between 100 and 300 are acceptable. From the KV ratio, you can figure out the rpm that can be generated. KV is nothing but rpm/Volt. So if you have a 100 KV motor and a 10V battery, you will get 1,000 rpms.
VESC control unit – VESC stands for Vedder Electronic Speed Controller. It is the central controller or the brain that controls the speed of the motor and hence the skateboard. A sensored motor will require a sensored VESC. Every VESC will have a maximum current (in Amps) that it can handle and a maximum voltage as well. So, depending on the battery that you plan to use and the current rating of other components, choose the VESC carefully. Also, try to find a VESC with UBEC. UBEC just means that the receiver can be connected directly to the VESC without the need for an external power source. Without UBEC, you will have to make provision for the power source and it may unnecessarily add to the components and space requirements.
Transceiver/Receiver – The transceiver or transmitter is the remote control or button that you hold in your hand. It is used to make the skateboard go forward or brake in order to stop. The transceiver sends a signal to the receiver, which then sends the signal to the VESC. People often use an RC controller or a Wii Nyko Nunchuck for the transceiver. You will have to buy the receiver separately as the transceiver is just a remote control.
Battery – There are two types of batteries used in electric skateboards. First is a lithium polymer (Li-Po) and second is a lithium ion (Li-ion). Li-ion batteries are generally regarded as more durable, but also tend to be more expensive than Li-Po batteries, which are somewhat fragile relative to Li-ion. Both types of batteries normally have a maximum voltage of 4.2V with a nominal voltage of 3.7V.
Battery Management System (BMS) – BMS is nothing but a battery management system. It helps ensure that the rechargeable battery used in the skateboard operates within safe parameters. It monitors various metrics such as voltage, temperature, state of charge, depth of discharge, current, etc. Choosing the right type of BMS can allow you to charge your skateboard battery using even a laptop adapter.
Anti-Spark Connector – Anti-spark connectors are used mainly for safety purposes. Since the battery is connected to the rest of the circuit directly, if something goes wrong, then your electrical components can get damaged. If you insert an anti-spark connector between the battery and the rest of the circuit, then you can disconnect the battery and the remaining electrical components using the connector. Also, you may note that the VESC unit can draw something like 60 Amps, which is a bit too high for a simple on-off switch to handle. So, just sticking in an on-off switch instead of an anti-spark connector can create problems.
Wires – You need good quality wire to connect all the different electrical components. A 10 AWG wire is good enough for the purpose. You can even use 12 AWG.
Enclosure – You will need an enclosure or a junction box to house all of the electronic components, namely the VESC, the Motor, the Battery, and the Anti-Spark Connector. You need to find a sturdy waterproof enclosure that can protect your electronics from water or from the force of getting crushed or scratched. You can either 3D print your enclosure or use a metal one. A wood enclosure may not be waterproof.
Deck – This is the longboard on which you will stand. It is the main body of the skateboard. Besides, you will also be attaching all your electronics to this board. A board with a length of 36 inches or more is recommended. The curvier the road, the shorter the board length while the straighter the road, the longer the board length. A wood board or an aluminum board is fine to make your electric skateboard. The more space you have on the deck, the better it is to mount all the electronics underneath. The best skateboard decks are made with layered wood and some fiberglass. Nowadays, carbon fiber decks are also available. A grip tape on top of the deck is a must for safety reasons.
Truck – The truck is a piece of metal that holds the wheels together and attached them to the deck. They are normally made of an aluminum alloy and are designed to withstand impact from landing hard and from bending and tilting when the rider wishes to turn the skateboard. The two ends of the trucks will have the appropriate design to fit the skateboard wheels. The length of the truck is normally 180mm, but a wider 218mm version is also often available.
Bushings – They reduce the twitchiness on your skateboard and also affect how the skateboard turns. If your weight is less, then use soft bushings. If your weight is more, then use harder bushings. The bushings are installed on the truck. There is a top bushing which is thin and a bottom bushing which is thicker. The top and bottom orientations are when the skateboard is placed upside down.
Wheels – This is one of the most important parts. Skateboard wheels are normally made from polyurethane. It will enable the skateboard to move freely. The bigger the wheels, the greater the ground clearance. This could be an important factor if your electronics box or housing has a lot of height. Bigger wheels also lead to higher top speed and greater stability. But you do lose out on torque and acceleration with a larger wheel. The most common wheel size is 3 inches as that size has a big enough hollow area for screws or bolts to pass through to the pulley.
Belt – 9mm belt with teeth is necessary to transfer the power from the motor to the pulley attached to the wheels of the skateboard. The belt is basically wrapped around the small pulley attached to the motor and the larger pulley attached to the wheel.
Pulley – Along with the belt, two pulleys with sizes of around 15T to 18T and 30T to 40T teeth is required to complete the motor set up. There are two pulleys to be attached. One goes on the motor while the other goes onto the wheel of the skateboard. The pulley on the motor is smaller, while the pulley on the wheel is larger in size. A 2:1 ratio is recommended between the smaller motor pulley and the larger wheel pulley. This ratio is also known as the gear reduction ratio. Make sure you fasten a washer on the outer side of the larger pulley because the vibrations tend to separate the pulley from the wheel. Use Loctite glue to secure the washer.
Screws, Nuts, Bolts – You will need various sized screws, nuts, and bolts to mount different parts and hold everything together. Also keep some Loctite glue at hand in order to fasten the screws and prevent them from unscrewing due to vibrations.