With the Solar Car Challenge growing closer by the day, the RAHS Green Energy Team is working hard to complete some of the biggest projects of the season; everyone is busy with something. The list of tasks we need to complete ranges from solar panel construction all the way to motor controller testing.
One of the biggest projects of the year is the construction of a new solar array to collect more energy from the sun. Currently, the framework on the car is in place and the soldering of the solar cells is almost complete. Some of our members have started working at University of Washington’s laminating facility (Washington Green Energy Testbeds) to laminate our solar panels. Once this process is complete, the team can add the connectors to the panels and begin the process of putting the panels on the car.
Kean Timblin (10) soldering solar cells
Another major focus for the team has been finishing the new battery and implementing it into the rest of the car. The electrical sub team has focused on ensuring the reliability of our battery management system (BMS). We monitor the voltage of individual battery cells as they charge to make sure the BMS balances the cells for maximum efficiency.
The team has also been working on molding a new windshield for better aerodynamics. We recently used a real world method of aerodynamic testing called tufting which is a process where you attach strings to the car in order to see how air flows over it in the real world. During this process, we found that the intersection between the windshield and the rest of the canopy was causing drag. The windshield that we are currently forming has a smooth transition to the top. The windshield was built by first making a mold out of foam and draping felt over it. Next, we made a box below it and drilled holes from the top of the windshield into the box. Then, we connected a vacuum to the box so that when the plastic windshield is draped over the mold, the windshield is suctioned to the mold. Once the mold was finished, we wrapped it in plastic and warmed it with heat guns until it became flexible and able to stretch. Next, we pressed the plastic to the mold until it cooled down.
Canopy mold in the process of being sanded
With less than a month to go until the race, testing the car has become a high priority. Up until very recently, we conducted most of our tests in an area around Boeing Field to make sure everything is working properly and that all subsystems are ready for the race. This past weekend, we were able to go to the Paccar Technical Center in Mount Vernon (with the help of our sponsor, PACCAR). With a track of this size, we were able to do testing at higher speeds to push our car to its limits. We learned that when subjecting the motor controller to high speeds for prolonged periods of time, the controller heats up. To prevent this, we plan to apply a heat sink to the controller. Testing our car informs us on how to improve it to be in the best shape possible for the race in Texas.