MIE.45 – A Financially Viable and Industry Competitive Longboard-to-Electric-Skateboard Conversion Kit

• Hamza Ayyoub
• Sam Jordan
• Miguel Ramirez
• Tyler Robinson
• Andrzej Szaflarski

With the increase in personal electric vehicles over the past decade, factors such as local accessibility and affordability act as barriers to purchase for many consumers. In consideration of this fast-growing market, ENGR, LLC., is seeking to sponsor the design of an integrable and cost-effective electric skateboard kit. Specifically, this kit will consist of electrical and mechanical parts–for example, the battery, motors, electronic speed controller (ESC) and handheld controller–required to adapt a traditional longboard into a fully operational and code-compliant electric skateboard. The sponsor required that the end product (the converted longboard) be portable, capable of achieving 15 miles in a single charge, with a rider weight capacity of 250 lbs. Additionally, the controller must be programmable such that torque could be adjusted to prevent dangerous accelerations. Range, watt-hour rating, and cost data were gathered toward comparison to the project constraints. From this comparison, a highly approximated relationship between range and watt-hour rating was discerned, in order to determine the specifications of an appropriate battery pack. The performed research supports that electric skateboards claiming to achieve between 15-20 miles had around at least 220 Wh. Selection of other fundamental components (motor, ESC, remote) was guided heavily by vendor availability, as well as overall compatibility with the designed battery pack. Design alternatives were generated, the major differences between each being battery configuration (either 7S3P or 12S2P) and electronic speed controller type. In line with these two differences, the final design features a 12S2P 350.4 Wh 8000 mAh 43.8 V battery pack, with a programmable VESC. The electronics are housed by a three-part, 3D-printed enclosure made of ABS for ease of assembly, manufacturing, and water-resistivity. Furthermore, the battery enclosure is designed to contain the battery pack such that the assembled board maintains a low center of gravity. Overall, the final design satisfies the sponsor’s range and profitability requirements by featuring a battery with a watt-hour (capacity) rating that exceeds that of competing electric skateboards, which claim to reach 15+ miles for the average rider. The safety requirement is satisfied by using components from reputable vendors, as well as a battery management system in the designed battery pack. The end product additionally features torque control via throttle profiles with the chosen programmable ESC (VESC). Finally, the project’s low-cost requirements are also satisfied in choosing components with a total cost under the project budget ($500). Relative to electric skateboards currently on the market, the development of this retrofit kit provides a much more affordable and accessible alternative to consumers, thus improving opportunities for profit and growth in an expanding industry.