Greetings from Pittsburgh Electric Propulsion! I first want to thank you for support of our team and program throughout the first year of our club. The trust and commitment you showed Pittsburgh Electric Propulsion as an unproven first-year team in the American Society of Naval Engineers’ Promoting Electric Propulsion for Small Craft Competition was remarkable and our team will be grateful to you for years to come. Without your support and faith in a small group of college students with an idea to build an all-electric boat, we would never have been able to accomplish the successes mentioned within this article. We are happy to report that in our first year of existence, we placed third in the Promoting Electric Propulsion for Small Craft Competition. This article will detail the work we did throughout the year, in the coming weeks you can expect to see a technical report coming to your inbox to detail the steps we took throughout the design process. We hope to retain your support in coming years, as we continue to grow and expand our team and projects to further interest in the field.
When you were originally contacted by us, we were a team of 2 people including myself. Since then, we have greatly expanded our team. After garnering interest from over 100 students in either graduate or undergraduate school, we formed a team of approximately 25 engineering and business students. With 4 members on our executive board, and 8 other members taking on lead design roles as technical engineers, we quickly formed a team of some of the most talented engineering students in the University of Pittsburgh. In addition to our talented group of engineering students we also acquired two exceptional members of faculty, Dr. Robert Kerestes (ECE department) and Dr. Tony Kerzmann (MEMS department), to serve as mentors and advisors to our team.
The first half of the year the competition year was largely based on laying out the framework of our team, battling through some school restrictions due to the Covid-19 pandemic, and researching and designing our project. It was in this phase of research and design that made the key decisions that followed. We decided to take a 1967 Mercury Thunderbolt 50 horsepower (hp) combustion outboard and retrofitting it with a MotoEnergy 1616 (ME1616) electric motor. The ME1616 is a Radial Air Gap, Permanent Magnet Synchronous Motor (PMSM) with an Internal Permanent Magnet Rotor (IPM)*. The controller that we decided to pair with the ME1616 was a Kelly 8080IPS sine wave controller. We decided to assemble our own lithium-ion battery pack by using Molicel 21700 P42A 4200mAh 45 A batteries. The final design we utilized had 25 cells in series and 20 cells in parallel, giving us over 6kW of power. The battery pack would be managed using the ENNOID LV BMS with a master-slave configuration. Finally, we needed to design the container that would house the battery packs and the extended tiller arm to control the direction of the boat. The hull we ran our system on was a Zodiac Milpro ERB 400.
After a successful first design phase of our project, we then needed to shift into manufacturing our outboard. During the manufacturing phase, we were lucky enough to have team members who, in addition to their engineering knowledge, were master machinist. They were able to perfectly create our aluminum adapter plate, as well as our coupling tool used to integrate our electric motor with our Mercury Thunderbolt. The extended tiller arm was also custom designed and machined by our team. This extended tiller arm allowed us easier control and maneuverability of our outboard. Our team also needed to reconfigure the cooling system that was included in the Mercury outboard to work successfully with our electric motor. This cooling system still needs some improvements to increase water flow, but we believe we are only a month or two away for it to work at full performance. Upon improving our cooling system, we believe we will have fully converted the Mercury Thunderbolt outboard.
The manufacturing of our battery pack proved to be the most labor-intensive portion of our project. We used 0.2 mm thick pure nickel strips to connect our batteries, and a pure copper busbar to improve battery performance. A kWeld battery spot welder was used to weld the nickel strips to the positive and negative battery tabs. We then were able to solder a second layer of nickel strips to our copper busbar to then put a second layer of spot welds onto our battery terminals. An Ennoid battery management system with a master unit connected to three slave units was then connected to ensure the safety and balance within our battery packs. Thermistors were then connected to the center of our battery pack into our battery management system to monitor our batteries temperature. A cut-off temperature was set at 60 degrees Celsius to avoid a thermal runaway situation. Fish paper was laid on top of our exposed battery terminals to provide added protection Kapton tape was placed around our battery for added structure and support. Finally heat shrink tubing was placed around entirety of each battery pack for added protection. Each pack was wired in series within our system via a 2 AWG wire and the entire pack was connected to our contactor. The contactor provided power to our motor controller, which converted our DC power into AC power for our PMAC motor.
As you can see, there was an immense amount of work and research done by the talented team of students at the University of Pittsburgh. None of this work would have been possible without the generous donations from our sponsors, which we are extremely grateful for! Next year we are further expanding our opportunities for students to be involved in the design of electric vehicles. We will be improving our current boat, as well as entering the evGrandPrix to design a high-speed electric go-kart. Additionally, if we can raise enough funds, we would love to add a second electric hydroplane boat with the goal of achieving the fastest possible speed. All of these are amazing opportunities for the University of Pittsburgh students. However, there is a dire need for additional funding to make them possible. We hope to retain the support of our current sponsors and gain additional sponsorships to help us make this program possible. Our funding goal for the following year is $75,000. This will make it possible for us to produce all three projects. We strongly believe that these projects will help to shape the future of engineers and help produce engineers that are ready to be large contributors to companies before they even earn their undergraduate degrees. We thank you for your interest and commitment to Pittsburgh Electric Propulsion and hope that we can retain your support in the coming years.
Captain & Co-Founder of Pittsburgh Electric Propulsion