![]() |
![]()
![]()
Double junction Gallium Arsenide solar cells and Lithium-ion polymer batteries work together to power the University of Missouri - Rolla (UMR) team to win the 2003 American Solar Race. The 339 pound vehicle, The Solar Miner IV, with 1500 Watts of power won this 2,300 mile national race by driving from Chicago, Illinois to Claremont, California in 51 hours, 47 minutes and 39 seconds.
![]()
Solar Power - A gift from the sun
Within a solar array, energy from the sun is collected by photons in the solar cells. The energy is turned into electricity which travels through the power trackers that maximize the amount of energy needed to run the car according to how much is being collected and the status of the batteries. The team was fortunate to have Gallium Arsenide double junction cells made by Spectrolab. Douglas Carroll, a UMR engineering professor, said the cells were about 22 percent efficient. These cells were the most expensive part of the car, running in the ballpark of tens of thousands of dollars. The cells were provided by Spectrolab at a deep discount; the cells were rejected for use on satellites because of the very rigid requirements for each application. However, these ‘rejected’ cells are still of high quality and are much more efficient than standard silicon terrestrial grade cells.
Full grade Gallium-Arsenide cells can run into the millions of dollars and are used in specialized space applications. Will some of the newer cells with higher efficiencies (35%) be used in a solar race soon? Probably not; they would be unbelievably expensive. As one person stated on the American Solar chat website, “You can’t afford them. However, Warren Buffet could maybe cover his car roof, but not the hood and trunk. And, then he’d be broke.” (Comment found on website, “Stuff that Matters - News for Nerds” in comments on UMR winning the American Solar Challenge.)
![]()
Power storage - Lithium-ion polymer batteries
The battery pack , comprised of 460 individual batteries, weighing approximately 460 pounds, is arranged so that the output is 100 Volts. The batteries have the ability to source over eight kiloWatts. Although the precise cost of the batteries is unknown, a figure, found in “Facts and Questions”- a published paper about the American Solar Challenge 2003, listed a price of $10,000 for a set of Lithium-ion batteries. The UMR team stated that the Solar Miner IV, UMR’s winning solar car, could run over 250 miles on a full battery charge with no solar power from the sun.
Vignettes of the race - following UMR on the race route
This is not a race where the winning team initially took the lead, sat on their laurels and easily crossed the finish line in first place. Challenges were encountered but the team was prepared to focus all its energies and resources to meet the needs for each day.
On the first day, the team had problems with their motor and had to replace it at a pit stop in Springfield , Illinois. Therefore, at Checkpoint 1, they were running third behind Minnesota and Waterloo. Although the new motor worked just great, the UMR team was still 19 minutes from the lead at the end of the first day.
On day two from Rolla to Albuqurque, the UMR team decided they would have to have to set a target speed of 55 m.p.h. to get ahead. Waterloo had a problem, so the UMR easily gained some miles on this team which had been ahead the previous day. As for Minnesota, the team had chosen a cruising speed of 50 m.p.h., so the UMR team was able to pass . In reflecting on this day, one of the team members made the comment - “This was the last time we would see the rear end of any solar car during the race.”
![]()
From Edmond to Sayre, the teams encountered some of the worst roads. A crack in the body of Solar Miner IV widened and the UMR team had to look for a plan to repair the vehicle. The team was fortunate to locate an alumni in Amarillo who was able to weld the vehicle.
The drive from Amarillo to Tucumcari went very well. However, during regular checks of the vehicle, one of the team members spotted a couple more cracks in the chassis, so another welder had to be found when the team arrived in Albuquerque.
The course from Albuquerque to Gallop provided no problems and the team pushed on to Flagstaff. Clouds began to form, so it was imperative to keep ahead of this sun-shielding front. The team pushed on to Flagstaff with sun shining on the arrays and completed the 435 mile trek for the day.
Being on a fast track to win the race, the team crossed the California State Line and encountered temperatures on the desert as high as 117 degrees F. They reached Barstow with each team member drenched with perspiration, but somehow the heat was bearable. UMR was in the lead and the closest competitors, Waterloo and Minnesota, were about two hours behind.The rest of the trip proved to be just as successful. The Gallium Arsenide solar cells and Lithium-ion polymer batteries performed magnificently. UMR kept their lead and placed first, with Minnesota, second and Waterloo, third. Fourteen months of designing, building and racing the car had resulted in a dream come true. Spending all of each team member’s free time on the race for many months proved to be a world class experience.
Racing - a great tool for teaching application of skills
The stated purpose of the ASC is not to bring solar cars to consumers but rather to inform the public about alternative energies and encourage young engineers to think about energy efficiency in their selection of careers.
For the team members themselves, the Race takes on a greater significance - life long goals of working together. As one of the students said on the UMR website, “The Team is like a small business, what we do involves interaction with peers, faculty administration, and world corporations, so communication is key. Learning how to communicate effectively helps in many facets of life. We have the opportunity to travel for testing, fund-raising and the race.... We are a team, so we have to learn to get along, keep on track with our goals, and share responsibilities through good times and bad....(But) knowing that you are a part of something that could make a huge impact in the future is fun!”
Enhancing the experience across America
No longer is solar racing left to a few students at the Universities. High school students are beginning to get involved. This July, a 1,500 mile solar car race was held for high schools wishing to participate in the program. The Dell-Winston Challenge began in Rock Hound, Texas and concluded in Cocoa, Florida at the Florida Solar Energy Center. The winning vehicle, the Sundancer ,was designed and built by high school students from Houston, (not Texas) a rural town in Mississippi with a population of 3,903. This is the third year that this team won the race, which is the largest, longest running high school solar car race in the world.
The Sundancer was completely powered by solar energy. This 722 pound, 17.5 feet long and 6 foot wide vehicle traveled at a top speed of 64 miles an hour but averaged 23.1 m.p.h.
A spokesperson for the Houston team, Sherrie Gail Springer, said, “It’s hard to describe how much this program means to each of us. We really feel like it’s helping us be better students, and also helping us get ready for the future. We’ll remember this experience for the rest of our lives.” (Ed Note: No extensive term paper could ever offer such a memorable learning experience.)
Beyond being a phenomenal experience for those involved (students, faculty, supporters and sponsors) in the American Solar Challenge and the Dell-Winston Challenge, it is hoped that these races will be the catalyst for companies, engineers, teachers, students, and communities to look at ways they can personally become involved in a environmental project which will lead to clean U.S supplied energy for the future.
There will always be some who say, “We don’t have the time,” or “this is way out of our price range.” But, fortunately, there are individuals who have persevered, found monetary support and joined with others to build a team; they have kindled life into learning and given students a hands-on taste of the future energy requirements for a better tomorrow. Each individual (or company or organization ) makes the choice to give (or not give) the next generation a taste of the excitement and challenges for what it takes to bring the green technology in its infancy today to full fruition tomorrow.
![]()
BD
![]() |
![]() |
|||||