UT Solar Vehicle Team Competes in Formula Sun Grand Prix
We have finished the 2010 American Solar Challenge.
We started at 10:12, finished at 2:03, so just under 4 hours for the 110 miles. We ran at 45 mph whenever the speed limit allowed. We ended with the batteries at about 25 percent charge. We finished ahead of 3 cars. The car ran perfectly.
Thursday we drove the solar car about 145 miles, almost making the checkpoint at Alton, Illinois.
Friday we drove about 120 miles, stopping about 4:20 to charge. We charged to 6 pm, and then trailered into Normal, Il, the end of stage 3 (we trailered just under 100 miles)
We started to notice a problem with one of our battery modules the last few days. It developed high impedance and wouldn't take a charge. So we replaced it yesterday, taking the penalty. It turned out to be a mechanical failure, almost certainly caused by the railroad tracks when the car went airborne. All but 4 battery cells broke away from their circuit board.
After replacing the module the battery pack seems fine. We reached about 75 percent charge yesterday afternoon.
This morning, Saturday, there is no sun unfortunately.
Today is the final part of the race, the finish from Normal to Naperville (110 miles). The race starts at 10 am, and the finish line closes at 2:30 pm. So a minimum speed is necessary, which will be easy for us if we get sun today.
In terms of the car performance, under full sun and 30 mph we have been using 400-500 watt-hr/hr. About half the power is coming from the battery, and about half from the array (2-3 amps from each at 85-90 volts)
Stage 3 has started, checkpoint at Alton, IL, 163 miles. We should be able to make it.
Up at 6:30 this morning, ready to charge at 7. But overcast this morning, so almost no charging. But it cleared off just before the race start.
We are off and running, race just started at 9 am. The live webcam is on (utsvt.com). No problems with our car and we have a close to full battery due to our charging yesterday afternoon.
In terms of our standing in the race, it is important to keep in mind that there are two classes: open and stock. The only difference is the solar array; stock is silicon and open is anything (most open class cars use gallium arsenide). We are silicon and we are really competing against other stock class cars - open class cars just have much more power.
5 out of the 13 cars that made this race are silicon: UT, Stanford, New Paltz, Northwestern, and Iowa State. It is a little difficult to know our standing, since the officials get our data later. But I believe we stand about in the lower middle of the stock class cars.
Update June 24th:
We left Warrensburg, MO about 9:45 am. We drove the solar car about 4 hours, making it to checkpoint 2 in Jefferson City, MO. No problems at all with the solar car. We stopped just outside of Jefferson City, as our batteries are at about 30 percent charge. About 100 miles today.
We are charging our batteries until about 6:30 pm today. We are getting about 8 amps of array current (the batteries are about 60 amp-hrs).
We will then trailer the solar car to Rolla (Missouri Univ of Science and Tech), as we must be there by 8 pm for mandatory stage stop 2 tonight.
Update June 23rd
We left the Neosho checkpoint about 10 am on Monday. We drove towards Topeka, the first stage stop. We decided to stop when our battery reached 60 percent charge, 155 miles. We charged about 2 hours, and left about 5:30. We had to trailer the solar car the rest of the way to Topeka (about 90 miles) to make the mandatory 8 pm arrival time. So we incurred a trailering penalty.
The only glitch was railroad tracks which bounced the car into the air, and broke a wire. This also caused a software glitch, and we had to reload the motor controller software.
Today (Tuesday) we started at 9 am with all the solar cars in Topeka, the start of stage 2. Almost immediately telemetry indicated excessive battery current. We stopped and determined the brake calipers were too tight, due to some adjustments the night before. So we lost about 3 hours fixing this, although we were able to bring our batteries back to almost full charge.
We got going about 2:30 pm, and everything went fine for the re st of the day. We made 126 miles for the day, and are now stopped and charging.
Since everything is working well and we have good battery charge we should be able to have a strong day tomorrow.
We are camping tonight, in Warrensburg, MO.
Max battery temp today was 43.8 deg c. Our battery is at about 45 percent charge.
Update: June 20th
We arrived in Neosho, MO at about 6 pm. This is the first checkpoint and the end of our raycing for today (118 miles).
Battery charge is about 60 percent. Maximum battery temperature was 41.85 deg C. It was 100 deg F when we left Tulsa, but down to 90 when we arrived here. So batteries are holding up well. We have set up our array stands and are charging (batteries get impounded at 8 pm). We can begin charging tomorrow at 7 am, and begin raycing at 9 am.
Our front wheel bearings are noisy and we are trying to do some improvements.
We are camping here at the checkpoint tonight.
We are quite pleased with today.
All went well this morning.
Race started right on schedule (noon). Everything fine with us.
We are enroute, about half way to the first checkpoint (Neosho).
Update: June 19th
On Friday we were up at 6 am to set up the car for charging.
At 7 am we got our batteries back from impound. We then charged for 2 hours.
At 9 am the final day of qualifications began. We got right out on the track.
Everything went smoothly with the car. We built up laps is the cooler morning, averaging about 3:30 on the 1.7 mi track.
Our battery temperatures slowlyclimbed. The new fans seemed to help. At 12:38 we brought the car in to cool the batteries (telemetry indicated 43.35 deg c, trip is 45 deg. We also changed the rear tire.
Back out on the track at 1:52 pm. Very hot on the track. Temperatures started climbing. More laps, back in once more to cool batteries. Only a few laps to go to qualify. Qualified. Two more laps. Battery under voltage trip. Battery pack depleted. We just made it.
Solar car performed flawlessly, with brand new electrical system. Our only issue is our old battery pack (2007) with 45 deg C max temp.
We left the track at about 7:30 pm. We got invited to dinner by an alumni who had been coming by during the week. We left cresson about 11 pm. Arrived Tulsa about 6 am this morning. Some of us had been up 24
4 hours sleep. Work on car to get our mechanical green. That is now done. Our lead and chase vehicle inspection should start shortly.
American Solar Challenge begins tomorrow at noon.
Update: June 18th
We have qualified for the American Solar Challenge!
It was a very exciting day.
Update: June 17th
We had a much better day today - 79 laps. A little disappointing, since 100 laps would have qualified us for ASC. But the afternoon heat once again caused our batteries to reach their 45 deg C trip point. So we must get 71 laps tomorrow to qualify (150 two day total).
Other than battery temp, the solar car is running great. No other problems.
We are going to try adding additional battery box fans tonight.
Keep track of our live webcam and info on our website.
Tomorrow will be difficult since we will not have a fully charged battery.
Update: June 16th
We got our mechanical " blue" first thing in the morning. Several people pulled an all nighter.
We were on the track at the start of Formula Sun Grand Prix 2010!!
We achieved 48 laps, way too low. Our battery overheated in the afternoon. It has been very hot here.
We moved the battery air intakes to the front of the car.
Update: June 15th
A problem caused us not to receive our shipment of parts today, so we really had to scramble. Several trips to local stores, borrowing bolts and nuts from other teams, etc. We finally got reinspected at mechanical at 7 pm. There are still a few issues. We are taking care of them now and will be back at mechanical at 7:30 am.
Hopefully we will at least get a mechanical "blue" and be allowed onto the track. Wednesday starts the track race, Formula Sun Grand Prix. We have to do 100 laps in one day or 150 laps in 2 days to qualify for the American Solar Challenge. Each lap is 1.7 miles.
Update: June 14th
We got our yellow in mechanical early this morning.
We passed dynamics today
Turning, figure-8, slalom: driver-George
We have started to disassemble the suspension to add the flex nuts the officials are now requiring. We expect the parts to arrive tomorrow morning.
Hopefully we will get a mechanical green tomorrow, and be ready for the track race Wednesday. We seem to be ahead of many of the teams, and should have a good starting position.
The car is running very well.
UTSVT is currently competing in the Formula Sun Grand Prix in Cresson, Texas. Track their progress at the team website where a live racing map, vehicle stats and live webcam are updated every 60 seconds. Later this season UTSVT will “rayce” their car, the Solorean, in the American Solar Challenge cross-country competition.
UT's "Solorean" previously participated in the 2009 Formula Sun Grand Prix, a track-based competition. Since then, the students have fine-tuned the vehicle to deliver better performance, and tweaked design to improve safety. The American Solar Challenge 2010 race from Tulsa to Chicago will deliver real-world feedback on how well they’ve done.