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NREL Hosts SEI's Solar Rollers RC Car Race

Posted by: chris
May 20, 2013

SEI's Solar Rollers RC Car Race a High-speed Success

The green flag waved at 11:30 am to start the one-hour race, which is a long enough period to test the overall energy efficiency of each car and its renewable energy generation system. From the very start one thing was evident: these cars were fast. The circuit was about 50 meters in length and within a minute or so all four cars were turning laps of less than 9 seconds. The fastest lap of the day was 8 seconds flat.

While the teams had each done testing on smooth tennis courts and parking lots, it soon became apparent that the actual race would not be so gentle on the cars. Impacts between cars were simply unavoidable as they negotiated tight turns at 20 miles per hour and cars could be seen bumping over lane dividers, banging into one another and even spinning like Frisbees at times. The foam bumpers students installed worked well but could not protect the mechanical systems underneath.

Soon, problems developed with every one of the cars. Pinion gears spun off, suspension components broke and critical bolts vibrated loose. Each team was forced to run their car to the pits for repairs at some point during the race. The pits were filled with activity as teams diagnosed problems and passed tools and parts back and forth. At one point, there was only one car left on the track - but most repairs were minor and quickly resolved.

In the end, durability and the ability to remain on the track turning consistent laps proved vital to winning the race. Aspen High School, which had the heaviest car at 1.9 kg, was the only team to opt for rear suspension in their design. Their car bounced its way to victory, completing 245 laps in one hour. Second place went to Yampah Mountain High School followed by Colorado Rocky Mountain School in third.

As fast as the cars were, they could have been faster. Cloud cover limited the power of the sunlight available to about 60% of what would be available on a clear sunny day. Some cars slowed toward the end of the race as their solar systems struggled to maintain full voltage in the batteries. On a clear day, the cars will generate 25-30 watts continuously and go faster throughout the race.

The Solar Rollers will race again on August 11 at the Aspen Science Festival Street Fair at Paepcke Park in Aspen. Solar Rollers is a new program for high schools from Solar In the Schools, the K-12 outreach program of the non-profit Solar Energy International. More information is available at

Race Results - At a Glance



Laps Completed in one hour 
(‾50 meters per lap)

Fastest Lap 


Aspen High School




Yampah Mountain High School




Colorado Rocky Mountain School



The demo car uses advanced solar cells and is ineligible for high school competition


Solar In the Schools Demo Car



About Solar Energy International 

Solar Energy International (SEI) was founded in 1991 as a nonprofit educational organization to help others to use renewable energy resources and sustainable building technologies through education and technical assistance.

Our vision is focused on helping create a more sustainable future for our planet and its inhabitants. Through our work, we see clear opportunities to influence people's thinking and behaviors towards energy efficiency and the use of natural, sustainable methods of energy production and utilization.

Solar Energy International is a 501(c)(3) Equal Opportunity Institution and Employer, and is not affiliated with any dealer, manufacturer, distributor, or any other renewable energy commercial enterprise.

Media contact for SEI is Christopher Turek, Director of Online and Student Services - chris(at)solarenergy(dot)org - 970-963-8855 x115 -


Noah Davis
Solar In the Schools Manager
(970) 963-8855 ext 114 

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