A quick update: Next week CalSol will be displaying GoldRush at the Marin County Fair as part of the Electric Wheels Car Show. Feel free to stop by the show and check out all the amazing vehicles that will be on display!
On Monday, CalSol’s trip came to a close. With GoldRush safely home, it is time to reflect on the journey that we embarked on. (Click here to see photos of the race).
First and foremost, we would like to thank our sponsors for their monetary and material support, without which CalSol would not exist. Secondly, thank you to all the team members who have toiled for many months, surrendering your free time, sleep, and grades to finish the car in time for Formula Sun. Lastly, thank you to all our families who have seen very little of us because we were “working on the solar car”.
While engineers are obsessed with performance and numbers, I think it diminishes the accomplishments of this team to dwell on the numerical results of the race. Yes, it’s true, we finished 9th out of 9 qualifying teams, with only 67 laps compared to Minnesota’s 487, but that doesn’t tell the whole story. The most amazing part of our race occurred before we even entered the track for the first time.
When we arrived in Texas, we had what we thought was a nearly complete car, needing only a few finishing touches on the electrical system before we would pass scrutineering. The electrical team focused its attention on the Battery Protection System, a critical system that monitors our lithium ion batteries for conditions that could damage them or start a fire. However, after 2 days of working on it nonstop, we decided that there were fundamental design flaws that would prevent it from working no matter how many microchips we replaced, how much soldering we did, or how much code we wrote. While less dedicated and resourceful teams would have called it quits and packed up, CalSol was determined to get out on the track and race.
Berkeley engineers may be criticized as “theoretical” and “not practical”, but there wasn’t any theory that would get us out onto the track. As we wrote earlier, after the race had already begun, we decided to switch to lead acid batteries, a much simpler chemistry, but also much heavier and with less capacity. Within a few hours, we had located a distributor of suitable batteries, planned the mechanical changes needed to accommodate the extra volume and weight, and mapped out the necessary electrical rewiring. By Thursday morning, we had debunked the myth and passed the remaining scrutineering tests.
And so every one of those 67 laps was a triumphant reminder of what we as Berkeley engineers are capable of accomplishing in spite of the most challenging circumstances.
Our next public appearance will be at the Marin County Fair on July 1-5. Come out and see GoldRush as a part of the Electric Wheels Car Show!
CalSol began the last day of the race looking forward to 10 hours of racing, but unfortunately we were unable to begin with the other teams due to some mechanical problems from Thursday’s racing, and also our brake lights stopped working. By 10:30 AM we had fixed the problems, tuned the suspension, and demonstrated to the scrutineers that our car was solid and safe. We quickly discovered that retuning the suspension improved our handling and made the drivers more comfortable on the numerous sharp corners on the track. After a couple of hours of racing, our driver came in to report hearing strange sounds coming from the motor. It took a while, but we finally determined to our relief that our motor was fine and that a bad wheel rim was to blame for the sound. With a replacement wheel on the car, we sent our drivers back out for the last 2 hours of the race.
Unlike the other teams who had drained their batteries after 3 days of racing, we had a relatively full pack, so we were able to finish the race very strong, lapping most other teams several times near the end. Everyone, from the race officials and corner flagmen to the other teams, was very supportive and flashed us thumbs up as we passed by. It has been touching to experience the camaraderie that the teams share, and we would again like to thank all the teams for giving us advice, loaning us tools and materials, and cheering us on as we made progress.
Hi ya’ll. We are on the track and raycing!
Still sleep deprived and determined to roll out onto the track we discussed many options and concluded that we needed to rayce. Despite our battery protection’s refusal to work we decided that we could quickly build a safe system using lead acid batteries.
Our chassis was not designed to hold car batteries so we drove into Fort Worth and bought lead acid batteries that were half the weight. We made some modifications to our chassis to support the weight of the newly purchased batteries which are still about twice the weight of our current lithium ion batteries, and only one half the capacity. We also had to re-wire all of our high voltage lines and re-program our driver-motor interface boards overnight. With a lot of work and serious lack of sleep, our electrical team pulled through and made the car work. I’d like to thank the generous teams and individuals that all helped our team pull through!
Today we passed both electrical and dynamic scrutineering! Our lead acid batteries were safe and our car performed beautifully in the dynamic tests. As CalSol entered the track for the first time, all the teams in the pit stopped what they were doing to watch and cheer us on. We totaled 24 laps in about two hours and impressed a lot of teams. Our fastest time on the very curvy, 1.7 mile track was 3:00 minutes flat!
We took a lot of pictures and displayed our sponsors’ logos proudly! We’re patching up some wear and tear on our car and plan to see you on the track tomorrow!
CalSol stayed up all night working on the car. We made a lot of progress on the electrical system although the continuous rain, thunder and lightning plus a brief tornado watch forced us to pack up our camp and delayed our progress. Despite coping with extreme winds and flooded tents throughout the night, our electrical team was able to resolve a communication error in our electrical system. Unfortunately, other hardware errors still persisted.
Sleep deprived and battered by the weather, ultimately the team decided that our untested battery protection system was not yet ready to cope with the bumps and bruises of an extended track race. After two sleepless nights our electrical team made the heartbreaking decision to pack up their tools and get some much needed rest. When the checkered flag dropped this morning we were not among the six teams that started racing.
The good news is that the race organizers have informed us that they will consider letting us join the race if we can finish the battery protection system and pass dynamic testing. However, even if our electrical problems prove insurmountable we still plan to continue to observe the race and learn from the other solar car teams and expert scrutineers.
Finally, and most importantly, we would like to thank all of our sponsors, the University, our friends and family for their support. Without all of them we could never have made it this far.
CalSol is in the middle of scrutineering. We have passed mechanical and basic vehicle inspections but we still have to pass electrical and dynamic tests.