Building an electric skateboard!!
By: Noyel Kalyani
Tags: Skateboarding, Electric Vehicles, Battery, Electric Skateboard

Like all solutions, it starts with a problem. Mine? I didn’t like walking. I know, I know, most of you are probably thinking; what a spoiled lazy brat! Not really. I exercise almost daily and I like walking if I have some decent company. It’s just that I don’t enjoying walking alone. I normally walk short distances (less than a couple of miles) and I get really get bored in doing so. I needed a more creative way of getting around and hence the idea of an electric skateboard struck me as lighting would to a pole on a building. Okay, okay, that’s probably pushing metaphors too far.

I used to ride skateboards back when I was in the “States”; but by no means was I an expert. I could barely do an ollie (a simple jump with a skateboard). It has been over 10 years since I have rode one. Nonetheless, I set out on the journey on attaining an electric skateboard. I had two options for doing so: easy and hard :O The easy way was to just go and outright purchase one that suited my needs. The hard way was to build one (#suspensefulmusicplaying).

Why must thou takest the easy route when the hard route shall teach thou the arts that thou hast been longing to learn! I thought to myself.

All in all, I chose the hard way out hoping that it would teach me a few things in some form of engineering since I have never had formal experience or education in engineering (P.S. My formal experience and education has been in Operations, Finance, and Biotechnology). Hence, I now decided to set out on a journey to build an electric skateboard, from scratch (#moresuspensefulmusicplaying).

TBH, it was more of a assembly process vs. a full blown build from scratch kind of thing. But hey, it did take some parts to be made, so at the end of the day, I learned a lot.

Let’s take a look at the building blocks of an electric skateboard, ingredients to build, if you may.

Skateboard (pretty obvious, please don’t read further if you didn’t think about this) Battery pack (I built this from scratch, excluding the battery cells and the Battery Management System (BMS)) Motor (mainly of 2 types: hub motor and chain drive, I decided to use hub motor) ESC (Electronic Speed Controller, the brains of the board) Compartment where all the electrical components will be situated on the skateboard

Boom! and your ready to go. Just kidding! It’s takes a little more effort than that. Its like a recipe. Of course, you have your ingredients, but those ingredients need to be mixed in a certain way and cooked at a certain temperature. Yeah, I know I said enough with the metaphors but, oops. Before I start, a huge shout out to Siddhant, my partner for this project.

Now, let’s get down to business!

Skateboard — at first thought, this seems pretty simple but alas, it isn’t. The material of the board matters a lot. Usually, skateboard are generally made of maple wood. This gives the board structural rigidity since maple really doesn’t flex much; and rigidity is usually always a good thing in moving vehicles. But, on a skateboard, especially an electric one, many prefer a mix of maple and bamboo. They prefer this because bamboo is flexible and can make for a smoother ride. You also have to decide on the size of the skateboard. A typical skateboard size is 32". A shorter skateboard is good for agility and doing tricks, whereas a longer skateboard is more stable especially for electric boards since you will be travelling faster than on a non-electric one. I have a very typical 32" maple board, and the only reason I went for this was convenience. It was easily available at a reasonable price point. My pick of the lot if I had the choice would be, a 40" inch maple and bamboo board.

My board also had 53 mm wheels on it initially, which I converted to 100 mm wheels so it will be easier to ride on the uneven terrain in Mumbai, India. Below is a look at the skateboard that I used in building my electric skateboard.

My 32" maple wood board

2. Battery Pack — Since we are talking about an “electric” skateboard, we have to talk about the component that powers the electric “stuff” on the board; and that would be the battery pack. There was also an easy and hard way here, and I yet again chose to go with the hard way by building a battery pack vs. buying one. Here is a picture of the finished battery pack.

My 10s2p battery pack of 18650 cells

What kind of battery pack should you choose? Batteries are batteries and what batteries do is provide power. But how much power do you require. To understand this in the most simplified way, you need to understand two terms: Volts (V) and Milliamp hours (mAh). Volts is how much power the battery is producing and mAh is the capacity of the battery. There is also configurations for batteries in terms of “series and parallel”. The more batteries you connect in “series”, the higher the voltage of the battery pack by the volts that each battery cell is capable of. The more batteries you connect in “parallel”, the higher the capacity of the battery pack that each battery cell is capable of. I decided to make a 36 V battery with a capacity of 5200 mAh. I used 18650 cells.

A picture of the type of cell that I used

The 18650 printed on the cell shows the type of cell, which is 18650 cells. The 26 confirms that the cell has a capacity of 2600 mAh. A typical 18650 has a nominal output of 3.6V and a maximum output of 4.2V. To achieve a 36V output with a capacity of 5200 mAh, I had to configure the cells into a 10s2p (10 cells in series, 2 in parallel) battery pack format. To do this, you have to weld the cells in a certain way. You can find many videos of this on the internet, hence I won’t go into the details of this. I hadn’t taken a picture when I spot welded the batteries together but here is a picture after finishing the battery back. You can see that the nickel strips are spot welded in a certain format.

Nickel strips welded on the battery cell

The battery pack has to be connected to a “Battery Management System” (BMS) to make it complete. The BMS does the following things: — control the charging of the batteries, controls the discharge, keeps the pack from overheating, controls the pack from overcharging, you get the idea, right? You can think of a BMS as a safety measure for the battery pack. Like mentioned previously, batteries are batteries and batteries provide power and a BMS is how this power is safely delivered.

Battery pack, unconnected to the BMS (silver housing)

Battery pack, connected to the BMS

BMS attached to the battery pack, with positive (red) and negative (black) leads

If I had done everything correctly, I should get a voltage output of between 36V and 42V depending on how much each cell is charged to. Testing it, it shows a pretty healthy output of 38.8V which falls right between 36V and 42V.

Multimeter showing a reading of 38.8V

We also need to charge this battery, so now we need a charger and connector that would connect to the battery pack. I decided to use a XT60 type connector.

XT60 Connector

For the charger, I bought a 42V laptop charger, striped the leads and welded the XT60 connector to it.

Battery Charger with XT60 connector

3. Motor — The motor is part that will propel the skateboard forward. Usually, there are two types of motors: a hub motor and a belt/chain drive; each of which has its pros and cons. There are also mainly two types of drive that can be configured: single drive and dual drive (there are some quad wheel drive that people have configured, this is usually for off-road use). I ended up using a dual hub motor set-up; I will expand as to why I did this after I explain some of the pros and cons of the above types.

Let’s firstly discuss the pros and cons of the types of motors.

Hub Motor: Hub motors is where the motor is actually located inside the wheel itself and the entire wheel is one unit so repairing this could be a pain in the butt. One of the pros of the hub motor is that when taking off and slowing down, it’s a more gradual affair and it won’t throw you off the board. Another pro for hub motors is that it’s pretty quiet while operating especially when you compare it with a belt/chain drive. Another pro as well as a con (the biggest one at that) is that it has one external moving part, the wheel it self. One moving part means that you only have to worry about that ONE thing. It also means that if something went wrong, the repair wouldn’t be possible unless you are an awesome engineer, and that means that you would just have to replace the entire motor. This could be a very costly affair. For example, typically the motor that I used can cost around USD 100–150.

Dual 100 mm hub motor that I used

Preview of how the hub motors will look with the skateboard

Belt/Chain Drive: This type of set-up requires a few parts. Firstly, it doesn’t come with the wheels and trucks (the axle of the skateboard), so you have to get them separately or just use the ones that came with the skateboard. Next, you need to get a motor and brackets. You will also need to get the sprockets and a belt/chain (whichever you prefer). You need to attach all the pieces like a puzzle piece to the trucks and the wheel. That was the first con of belt/chain drive; it takes a little bit of assembly. Another con of the belt/chain drive set-up is that the acceleration and slowing down is pretty abrupt, and if you are a new rider, this will throw you off the board pretty easily. One more con is that this type of set-up is fairly loud with moving mechanical parts. The biggest pro for this type of set-up is that you can easily maintain and repair it. This will definitely save you some “moola” $$$ in the long run, especially is you are planning to use the skateboard regularly.

Bonus: If your battery runs out, the hub motor board can be pushed and ridden easily; whereas a belt/chain drive board will have to be carried.

4. ESC — Electronic Speed Controller (ESC) is the main computer for the electric skateboard. It controls how the power gets put down. The ESC comes with a remote. It signals the motors to move forward or reverse and at what speed. The particular ESC that I ordered came with a remote that had 4 built-in speed settings ranging from slow to fast. There is notable difference in each of those modes.

ESC with remote

ESC without remote

ESC remote controls

You can see the entire set-up before assembling everything together.

Full set-up preview

5. Compartment — This has to be the most simple part this project and its where everything comes together. Obviously, the motors get attached to the board, but what about the battery pack and ESC? You have two options: to fit it above the board or below the board. The more usual way is to fit it the electronics under the board, however, I chose to go with fitting them above the board.

The completed set-up of the electric skateboard

So now, the electric skateboard is finally complete. I have been ridding this board for about 6 months now. I have done various tests on it including: riding on wet surfaces, top speed run, distance run, ease of use, tiredness after continuous use, reliability of parts, heating of parts, etc. oh and of course, the*all guns blazing run* (I will explain what this is below).

Riding on wet surfaces: riding on wet surfaces is okay as long as you have a water tight compartment to keep all the electronics dry. I actually first started riding the electric board during the monsoons and had to keep the electronics dry.

Top speed run: when I did the top speed run, I weighed about 70 kilos (about 155 pounds). I did it on a flat, not smooth surface. I was hoping to get to 20 kmph. I tested it, and got between 25–30 kmph. I was happy :)

Distance run: I did this run at around 20 kmph with me on it and on a fairly flat, not smooth surface. I was aiming for 10 km, I got to 12 km. Again, I was happy :) :)

Ease of use: I got my 10 year old cousin, who had never rode a skateboard, I got him to ride it without my intervention in about 10 mins. It can’t get easier that, now can it.

Tiredness: okay, to be pretty honest, riding on Mumbai roads for more than 3 km, the legs and feet just started vibrating. After a while, you get used to it though. Maybe next time I will make one with some type of shock absorbers.

Reliability: I have been riding for 6 months, everything’s been fine. Just lately though, I have started seeing wear on parts. The motor sometimes makes a noise which sounds like gears grinding against each other or gears skipping. On the last all guns blazing run, the plastic coatings on two of the leads from the ESC to the hub motor burned when they got really hot. It still works perfectly fine though. The video posted below is after the gears started making noise and after the plastic coating burned from the heat during the last all guns blazing run. Please note that this was not a high speed run, since I was on the terrace of a building.

Quick ride on the terrace

Heating of parts: the parts tend you get pretty warm, especially the ESC and the connector to the dual hub motor. The motor itself remains pretty cool, relatively. After the monsoons, I drilled some holes in the electronic compartment to aid the cool down of the parts, but this was in vain :(

Now, the test that you all have been waiting for, “the all guns blazing run”.

All guns blazing run: I ran this test multiple times during the last 6 months. This test consisted of me riding the board at the highest setting, at the top speed, on uneven surfaces, in very hot weather, simultaneously and continuously. I got a total of over 6 km on doing these tests. This was me pushing my board to the limits, and hence the name :D

We are finally done with the making and testing of the electric skateboard. Thanks a lot for sticking with me for this post. I will just make some closing remarks before ending this. The idea of a electric skateboard struck me because I really wanted a more creative way of getting around. Most of the parts were ordered online from US and China. I also had to order a electric spot welder to make the battery pack. The cost aspect: all in all, the entire set-up cost us about INR 40,000 and 40 hours of work. This includes everything. The cost of just the electric skateboard is lower since the total cost includes some one time purchases like the spot welder among other few things. The board was completed in a span of 6 months. The posts just highlights some of steps. There have been many problems along the way, but nothing that can’t be conquered.

If you have any questions please feel free to contact me (Noyel) or Siddhant. You can reach us on our email or Instagram handle.

Noyel’s email- yesnoyel@gmail.com

Noyel’s insta- noyel_jerry

Siddhant’s email- siddhantpawar000@gmail.com

Siddhant’s insta- el_loco_sid

Sayonara folks, it’s been a pleasure!