THE STORY OF THE ELECTRIC LONGBOARD

Version four is comprised of nearly five years of research and development.

This time I wanted the smoothest and most pleasant ride possible. If version three was a Formula 1 car, version four is a Rolls Royce. Mostly recycling parts from version three, I came across a few challenges.

Having taken AP physics at school, I had a really good understanding of electromagnetism and I wanted to incorporate it into my final build. There is a control mode called FOC (Field orientated control) in which the magnets in the motor are given proportional current as opposed to On/Off with traditional control modes. The result was a sinusoidal cycle between the three magnets which made for extremely smooth acceleration and braking. FOC is also a lot more energy efficient, which consequently makes the motor run a lot quieter.

However, FOC is not as robust as traditional control modes. For this reason, I had to cut the battery voltage to 42V to avoid exceeding maximum RPMS. This process involved re-building the battery to a 10S configuration, and installing a new BMS (battery management system). Fortunately, I had upgraded my equipment which allowed for reliable soldering and safer connections.

In conclusion, I had finally achieved the quality of a production e-board. However, I plan to bring the board with me to college so I can further improve it and turn it into something resembling a Tony Stark invention.

VERSION 3

Version three happened after moving to the US. It was the product of my dissatisfaction and therapy for feeling lonely after the move.
My goals this time was simple. I wanted speed and reliability. This meant stiff, robust and water-tight construction.
Leaving all of version two behind in Singapore with a friend, I saw an opportunity to re-consider all of the components, especially since living in the US allowed for far more accessibility to more options. And two day amazon shipping. The longboard-parts on this board were all trusted name brands, known for their downhill hardware.
The enclosure was fibreglass, custom made by a community member. Realising how fast 34 mph was, I didn’t want to take any chances with hardware flying out from vibrations.
The battery was a 12S2P set up (50V, 30A) which was a huge increase from the first two boards. This opened doors to far higher top end speed. The motor coupled with it was a lower, 190Kv which was also a considerably larger package, dishing out higher efficiency, conserving far more torque.
The vesc was also upgraded to a FOCBOX, essentially just a glorified VESC with more robust components.
Version three also featured **bluetooth connectivity** for realtime telemetry. It helps to know what’s going on inside so that problems can be diagnosed before they get worse.
I stayed with a single motor set up, both for cost reasons and so that if the electronics ever fail, I won’t have too much resistance manually pushing the board.

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VERSION 2

Version two was a huge improvement. Recycling parts from version one, I had saved on a huge chunk from the costs. The total budget for this was $500, with most of it being spent on the new deck and new hardware.
The battery and motor combination remained the same. It had worked for version one so I saw no reason to replace it. However, the new deck was flexible which meant I couldn’t place any hardware in the middle of the deck since stiff enclosures mounted on a flexible deck is never a good idea. This is the main idea behind the popular split enclosure design. However, still being a novice, I encountered many challenges.
The split enclosure called for an extended battery wire to stretch across the deck into the ESC box. Unfortunately, my soldering iron was still too basic. It didn’t have temperature adjustments and would not get nearly hot enough to solder 10AWG wires. My solution was to rip out the three (pos, neg, ground) 14AWG aluminium wires from an unused charging cable and individually solder them in parallel with one another. This effectively created the equivalent of a thicker, 10 or even 8 AWG wire. A black braided shroud was used to hide the ugly tri-color subway lines.
I also upgraded the ESC to the popular VESC - an open source ESC developed by Benjamin Vedder specifically for electric skateboards. It featured more programming capabilities and since it was open source, many people had already written libraries for polynomial acceleration curves, cruise control, and many more fancy luxuries. However, at the time, the VESC was still considered new so it came with a hefty price tag of $170USD.
Programming the VESC to my specifications was an undertaking in itself. It took months before I had a good grasp on which variables controlled what, and how an ESC instructs a brushless motor how to turn. Learning the technical details had also put me way ahead at school when it came to physics, specifically the electronics units.
A new enclosure for the VESC was also needed, and having confident abilities with CAD, I designed my own which I uploaded to Thingiverse for other people to use: https://www.thingiverse.com/thing:2264273
The sprocket and chain drive from version one was also too noisy and so it was replaced with a belt drive train, making sure to keep the ratios the same.

VERSION 1

This was my debut into the electric skateboard building world and so understandably, the budget for this project was ~$300USD.
This was the first project I had ever worked on that dealt with high current and sensitive hardware. For that reason, it was wise to stick to pre-built parts and though I was already quite experienced with soldering, I didn’t have the equipment for soldering wires as thick as 10AWG.
The battery was pre-welded by a local welder in Singapore and was configured in a 6S4P arrangement (6 in series with parallel groups of 4) which outputted 25 volts at 60 amps maximum discharge. I decided to keep the voltage low so that I could cheap out on the motor, getting a higher Kv (revolutions/volt) and a smaller package without sacrificing too much torque since I had 60 amps available.
The speed controller (esc - the brains of the board) was a cheap high current RC car controller which consequently had limited programming capabilities and had a very steep and unpleasant acceleration curve.