Electrifying a Jet Ski: Designing & Manufacturing an Electric Drivetrain for a Personal Watercraft

Abstract

While many vehicles are well into their transition to electrification, marine vessels are lagging behind; specifically, there are very few electric personal watercrafts (PWC) on the market. Though many engineers and hobbyists have retrofitted combustion engines for cars, motorcycles, and other automobiles for electric propulsion, there are almost no examples of electric conversions for watercraft. This thesis details the designing and manufacturing process of an electric drive train into a 1997 Yamaha Wave Venture 760 Personal Watercraft (PWC). This project aims to serve as a proof of concept for interchanging a combustion engine from an older PWC with an electric motor and Lithium-Ion battery. I performed rigorous calculations to properly size a battery and motor to propel the watercraft. Upon learning to weld, build battery packs, and configure a battery management system, I prototyped extensively—iterating upon battery packs and pack configurations. I assembled a final 72V, 10.4 AH battery pack with waterproof housing to power the 5kW motor that I coupled to the existing impeller drive shaft. Lastly, I performed a dry test monitoring the battery and motor health, confirming successful retrofit of the electric drive train, proving the feasibility in electrifying a used personal watercraft.