Solar Car Challenge
I competed as part of the RAHS Green Energy Team in the 2019 Solar Car Challenge. Over the course of a year we designed and built a full scale solar car for competition. We manufactured, and assembled parts and did extensive testing to optimize the performance of our car.
During the race at the Texas Motor Speedway we finished 1st in the advanced division, driving 988.5 miles over the course of four days of racing at an average speed of 32.3 mph.
Full CAD model of the mechanical components of the car
The design work was all done in Autodesk Inventor and Solidworks, and the parts were mostly fabricated in our school's machine shop. I was responsible for the design and construction of the aerodynamic surfaces and the solar panel array, as well as many of the electrical components of the solar system.
We designed and ordered a custom solar array to match the desired voltages of our electrical system after unsuccessfully experimenting with assembling our own array from individual cells.
An early version of the car's drivebase
The car's custom suspension system
Spot welding together the battery pack
The car's fully assembled powertrain
The solar array in charging configuration
The car's battery is comprised of 476 li-ion cells spot welded into a ~4.7 kWh battery pack. The battery is charged by the solar array, the power output of which is managed by a set of Maximum Power Point Trackers which optimize the load placed on the array to achieve peak efficiency. The car is driven by a single hub motor on an outrigger wheel on the opposite side of the car from the driver.
Motor energy consumption as a function of velocity
I was also responsible for the race strategy during the event. We installed a GPS in the car which live streamed data to a website for analysis. We did extensive testing prior to the race to characterize the car's energy usage as a function of velocity. I then came up with a model to approximate the solar power generation over time. Combining these models enabled us to optimize our energy consumption and maximize the distance we could drive each day.
Solar array power output as a function of time
