American Solar Challenge 2003
CalSol, the UC Berkeley Solar Car Team, placed 2nd in Stock class at American Solar Challenge (ASC) 2003. This ASC2003 ran from Chicago to Los Angeles along Route 66 and was 2300 miles long. It covered diverse terrain from mountains to desserts to hills and plains. It also forced teams to deal with different weather conditions from 120F heat waves to pouring rain and thunderstorms. We entered our newest car, Solar Bear, in the race. Solar Bear placed first in its class at Formula Sun Grand Prix in May. The car ran well and was very reliable. With a race crew of 8 people, we drove the solar car and 3 support vehicles across the country at speeds reaching up to 65 mph. Over the course of the race, the average power usage of the car was just 847 watts, slightly more than 1 horsepower and less than the power required to run a hair drier or toaster.
The race started off badly for us. While sitting on the starting line waiting for the green flag, we discovered the our NGM motor controller had failed sometime during the night. The motor controller is a critical piece of hardware that interfaces between the cars main power system and driver controls and the motor itself. In this case, the motor controller was causing the motor to go to full power for very brief periods causing large, dangerous jolts. While we were trying to debug the motor controller problem, a magnet broke loose from inside the motor, ruining it as well. At this point we were very close to having to withdraw from the race.
We were lucky to find the that University of Kentucky was willing to let us use the motor and controller out of their car since they hadn't qualified for this race. They let us borrow a brand new $17,000 motor and controller without hesitation and we can't thank them enough. Within 2.5 hours of discovering the problem, we'd swapped the motors between our two cars and were ready to drive. Many people who came to watch the start of the race in Chicago stayed with us to lend moral support and an extra hand if needed and really made the processes much more fun and less stressful. Some people from Kentucky elected to travel out to California despite not being able to race their car so when not sightseeing along the route, they were often near us ready to help out or have fun with us.
The first few days of the race were beautiful and very sunny. We were shocked to find that the Midwest and plain states are not as flat as we had always been told, there are hills everywhere. The people we met when we stopped for the night were wonderful. They were all very friendly and interested in the car and what we were doing. One older couple even brought us a tray of brownies.
One of the most exciting parts of the race were the parts that took place on the interstate. Most of the race is kept on the frontage roads that parallel the interstate or parts of old Route 66 but at times that isn't possible and we were forced onto I-44 or I-40. The adrenaline really flows when you take a homebuilt car with a maximum of 10 horsepower onto the interstate with cars that average 150 HP and huge trucks. The solar car was always surrounded by two of our support vehicles to protect the car, the lead in front and chase behind, but especially for the people in the chase car, the interstate is a constantly terrifying time. We averaged 35 mph on interstates while most cars were traveling at 75-80. The worst part about it was the people who would slow down to our speed in the lane next to us and try to get photos. Several times, semi's came roaring up behind these cars and had to slam on their brakes to keep from hitting them. A semi with smoking tires is not a sight you want to see three feet from a solar car.
The most memorable event of the race occurred on the interstate. We'd just entered a region with signs that read "Severe Cross-winds" and we could certainly tell that the signs were accurate. The solar car had just descended a hill and was traveling at 45-50 mph when a huge semi came speeding by and passed the car. The combination of the high cross-winds, chaotic wake left by the semi, and the solar car speed somehow managed to rip the top shell of the car and the solar array off the car. Luckily, the shell snagged on the back of the car so instead of being run over by another semi, it was dragged behind the car for a few seconds until the driver calmly pulled to the side of the road. After checking on the driver and finding that he didn't even have a scratch, we were shocked to see that the array was perfectly find, none of the cells even cracked! The only damage to the shell was a few scratches down one side where it scraped on the road, there was no real structural damage. We put the car in our trailer and drove to the next checkpoint to make the attachment method a bit stronger and by the next morning the car was ready to go and you couldn't tell anything had happened.
We had great weather for most of the race. There were a few fairly cloudy days but for the most part we out ran the clouds. There was one day that the weather didn't cooperate. Just as we were leaving Gallup, NM we hit a huge thunderstorm. There was lots of lightning all around us, and the rain was traveling horizontally due to the high winds. At the peak of the storm, we were driving through water 3 inches deep and visibility was almost nonexistent. While some teams pulled over and stopped, we decided to keep going to push through the storm and find the sun again. About 30 minutes later, the rain had completely stopped and we were getting great power off the solar array. The next day we discovered that a few drops of rain had sneaked into our electrical compartment and shorted out one of the power trackers for the array but we quickly bypassed that and never had any additional problems.
As a Stock class team, we were required to use Lead-Acid batteries and a 14.5% efficient solar array. The batteries added 250 lbs to the car and the array was much less powerful than those of other teams. As a result, racing in Stock class is much more difficult than racing in the Open class where they can use any type of batteries and whatever efficiency array they can afford. Climbing hills in particular is much harder for us that for the lighter cars. On the whole, Stock class requires much more strategy and planning ahead than Open class. This makes the race more interesting but also fairly frustrating when you get to the points where you just don't have the power to make it up a steep hill or you get to the interstate and you can't keep the minimum speed up for long enough.
The last segment of the race was great. It was mostly downhill so we got to go much faster than we normally would have. As we crossed the finish line we were happy to find out that there were a huge number of Cal students and alumni who came out to cheer us on. It was a great welcome back to California and a wonderful way to end the race.
CalSol finished in 2nd place. Our official time was 110 hours to finish the race, which includes penalties for tailoring the car at times. We are very happy with our performance. Route 66 is a punishing road in a normal car and we are ecstatic that our completely student built car was able to work so beautifully despite weather, terrain and road conditions.
To see more photos, check out our Photos section.
You can also check out the official race website for more information about the race and additional photos. http://www.americansolarchallenge.org.