Alex Toombs, Jake Thordahl, Mike Mellitt, Pat Bowlds and Ben Coffey


Gasoline power vehicles have been the norm since before even Henry Ford’s Model T began rolling off assembly lines in the early 20th century. Refined gasoline, sourced from fossil fuels, has remained inarguably the best transportation fuel source due to its high power and energy densities per weight and volume compared to any other fuel source, meaning that a tank full of gasoline can take you much further than an equivalent weight or size of almost any other material. However, gasoline has become an unsustainable fuel source over the past few decades as fossil fuels have been found to be nonrenewable at a pace that the world can keep up with. As development continues and demand for petroleum-based products continues to rise, pollution levels in developing nations become a concern thanks to the byproducts of petroleum refinement and consumption. That demand cannot be met with the reserves of oil we now have, meaning that soon an alternative must be found. As long as transportation remains important to us, the energy we use for it must be at the forefront of thought. Now, like never before, is the right time to consider hybrid and electric vehicle systems. Vehicles that are partially or wholly electric, including the Toyota Prius, Chevy Volt, and Tesla Model S are seeing unprecedented commercial success. The materials for high energy and power density batteries are being developed right now, with new and improved technologies coming out annually while gasoline engines stagnate. The goal to prove that both cars and even largely recreational vehicles like motorcycles can be powered by batteries led to the genesis of the electric motorcycle project between the Department of Engineering and Department of Energy at the University of Notre Dame over half a decade ago. As the public becomes more environmentally conscientious and a desire for alternative fuels grows (with less pollution) so too does the desire for a battery based electric vehicle.

The main goal of this project is to enhance the charging system for the existing electric bike. The former group who worked on the bike had a less than ideal charging system that rectified wall voltage at 120 V AC 60 Hz three-phase power down to a suitable voltage for their project. Eventually, this charging led to the damaging of the Optima Yellow Top batteries that we used, meaning that we had to spend a lot of money (approx $1200) just to replace the batteries the motorcycle used before beginning to test our project. Taking the previous groups’ frame, mounting system, batteries, and motor controller, our goal was to improve the charging and peripheral display subsystems to a point where the vehicle could be used more frequently.

Our new charger had the goal of following the specced charging profiles as per Optima’s website while allowing for a shorter charge time and a reconditioning period that should extend the lifetime of the batteries. At an average cost of $160 per battery while using a total of six batteries in the stack, preserving lifetime is of the utmost importance. Well-maintained, a stack of batteries in a Tesla Model S can last up to 10 years. A great deal of engineering goes into allowing those batteries to safely charge and discharge in a way that provides a stable ride while allowing the batteries to live indefinitely.

While electric vehicles are still far from the norm, sound and safe charging practices can go a long way toward making batteries more feasible. Our exercise in controls has shown the need for more reliable and accurate charging systems. A motorcycle provides a unique opportunity to prototype an electric vehicle due to its small size, short usage intervals, and low cost to maintain. As the world turns more toward electrical systems to meet its energy needs, well-designed and precisely engineered battery systems will be necessary to supply the power that the world demands.

Motor Controller Explodes