On Saturday, July 23 2023, the RAHS Green energy team traveled to PACCAR Technical Center with the goal of finishing the year strong with a full final day of testing. We decided to push our solar car to the limit in an eight-hour endurance challenge to see how many miles the new car could drive in a single day powered only by the sun. In the morning, a variety of factors changed our philosophy for the day. For instance, the shade created by the densely forested area around the track and the cloud-cover throughout the day made us decide to turn the day into a celebration rather than a challenge. Though testing the car, the team decided it would be best if we had more frequent driver changes, allowed our mentor and advisor to drive the car, and slowed down driver changes to a leisurely pace, making 18 driver changes throughout the day. Speaking of adults driving, we also took the opportunity to allow parents to drive. These changes would not be ideal for the race day we were trying to simulate, but taking the day slow would make a better experience for the whole team. In spite of these restrictions, we tried to drive as far as possible.
(Zach Olsson(12) driving Sockeye at PACCAR)
Using the data from the previous weekend of testing, our strategy team created an equation to determine the car’s efficiency at any given speed within the range we tested. As for energy input, our solar array had only come together the previous week, so we had to use last year’s car as a reference point. Throughout the day, the strategy team communicated adjustments of speed to the driver based on cloud cover, solar energy and battery percentage.
(digested telemetry: power vs. speed)
To our joy, the car had no major issues. In fact, we were testing a new system for cruise control which had a coasting feature; the car was so efficient that it sometimes was hard to tell if the cruise control was on or if the car was simply coasting. In total, we drove 270 miles with an average speed of 33 mph (about 53 kph). Over the course of the eight hours and including charge from our solar array, the car’s battery had only depleted to 52%, which would have left us a considerable surplus of energy to use the following day if we were participating in the actual Solar Car Challenge. Given our restrictions, the day could have gone worse, and the car worked as well as we could have hoped!
To celebrate the successful day of testing and say goodbye to the graduating seniors of the team, we regrouped Sunday to eat and tour cars at Derby.
(Atticus Caudle (11), Hika Harris (10), Jaxon Boyovich (10), Hagen Rankin (12), Otto Elenga (10), Hai lin Truman (Graduated), Lucien Freemesser (Graduated), Riley Wiggen (11) and Sukhman Khangura (11) eating lunch at Derby)
As for the future of the team, the 2023-24 GET RAHS Team is in the planning phase. The next step is to brainstorm upgrades for next year so we can bring a perfected car to Texas for the 2023-24 Solar Car Challenge if all goes well. Stay tuned for more details in the future!
(Larsen Matthew Mendoza(10) ensures all subsystems are plugged into our main board at the start of the day)
(Zach Olsson(12), Lucien Freemesser(Graduated) and Atticus Caudle(11) tape all of SOCKEYE’s seams to decrease drag)