Apogee was a beautifully built car that was both mechanically sound and electrically advanced. It raced in the 2009 World Solar Challenge, placing 10th overall. It also raced in the 2010 American Solar Challenge where it placed 4th overall. Testing for the car included track days at the famed Laguna Seca Racetrack. Dictated by 2009 WSC rules, the Li-ion battery pack weighed only 20kg. Post race analysis revealed that the aerodynamics could have benefited from less top shell curvature and less separation around the bubble, however the real performance bottleneck came from the underproducing MPPTs. The 800W that was generated at solar noon was only 72% of the designed power output. Even with the room left for improvement, Apogee performed admirably well. The team learned a lot from the Apogee build cycle and used the knowledge gained to improve upon older generations through testing and more advanced designs.
Equinox was designed for the 2007 World Solar Challenge. It was an ambitious build, boasting a top speed of 83mph, 200 miles on a single charge and a multijunction array. It was the same shape as Solstice but exchanged the space frame body for SCCP’s first carbon fiber monocoque body. However, the ambitious designs and longer than expected build cycle left very little time for adequate testing. The team faced a combination of electrical and array obstacles for the first 1,800 kilometers before a blown tire retired the car from finishing the race. Equinox marked the last of SSCP’s cars to have the driver laying nearly parallel to the road in the driving position.
Built for the 2005 North American Solar Challenge, Solstice was one of SSCP’s more successful vehicles. In the 2,500 mile race from Austin, Texas to Calgary, Canada, it placed 1st, narrowly edging out Berkeley’s CalSol team. Solstice traveled at speeds of up to 65mph during the race and marked a turning point for the team into becoming a serious contender capable of engineering high quality, advanced cars. While the engineering was rapidly improving, team experience was still catching up as evidenced by several mildly amusing blunders during the race. These included forgetting to waterproof the electronics compartment and using diapers as a temporary solution as well as a more serious miscommunication between the driver and chase vehicle that resulted in Solstice being rear ended mid-race. The latter almost cost the team the victory as after replacing damaged solar cells, the team forgot to turn the new part of the array on. The gaffes didn’t end there as long after the race concluded, a freshly joined team member accidentally bumped Solstice into a former University President’s personal car. Since then, the team has gained considerable experience and polish as demonstrated in the near flawless performances of Arctan and Luminos.
The Story Behind Solstice
Owing in part to a desire to distance itself from the negative experiences of ASC 2003, the team took a break from solar cars during the Fall and Winter of that year. During those months, the team assessed the feasibility of a completely different design project: a long-range pure electric vehicle — with the ultimate goal of driving from San Francisco to Washington, DC on a single charge. Through a highly iterative design process, the team developed a prototype chassis and several body designs. And while the team’s level of experience and the involvement of several highly knowledgeable alumni would have put the team in a strong position to build a successful vehicle, the long-range EV project was abandoned in March of 2004 due to the prohibitive amount of R+D that would have been required. SSCP decided it would not be able to support the financial and personnel requirements of that project.
At this point, the consortium of alumni and team members split: the Solar Car Project decided to build a new car for the 2005 North American Solar Challenge (Solstice). (It’s worth noting that SSCP alumnus and consortium member JB Straubel was still able to get his fix of EVs: he has since become the CTO of Tesla Motors). With renewed resolve, the team defined a new goal: Win the 2005 North American Solar Challenge.
For the next 12 months, the team worked steadily toward an April 1, 2005 goal of a fully-testable vehicle. With the exception of a few bumps in the road, construction was fairly smooth — the team finished on April 3rd with all systems (except the array, which was delayed by a vendor) integrated and ready to test. Local testing began, followed shortly thereafter by Central Valley test drives: camping at an I-5 rest stop, getting kicked out of Foster’s Freeze, and (most memorably) a weekend spent in the Carl’s Jr. parking lot in Chowchilla, CA.
In early May, the team unveiled Solstice to the public — and barely had time to catch its breath before a contingent of team members took the car to Topeka the following week for NASC early qualifiers. While the car passed scrutineering, electrical problems prevented Solstice from logging the required number of qualifying miles. Exhausted and frustrated, the team headed back to campus to overhaul the car’s electronics and improve mechanical systems. Over the next several months, the team logged more than 1600 test miles on Solstice, gradually shaking out bugs along the way. In July 2005, the team headed to Austin for scrutineering and final qualifiers. Aside from a minor brake mishap, scrutineering and qualifiers were exceedingly smooth: the team even secured third starting position from qualifying laps. Solstice had by this point logged over 2000 miles of driving.