As we get closer and closer to our end goal of having built a functioning solar car, there is one missing piece of the puzzle that grows increasingly more apparent: How can we have a functioning solar car without solar panels? While we have made progress on this front, there is still quite a bit of work that needs to be done.
Late in the previous year, we began researching and designing potential solar panels. This process involved choosing what types of solar cells we would be using, what our array would look like, how many individual panels would fit into the array, and much more. Finally, we settled on a 484-cell layout arranged into seven individual panels sections. To make this work we also decided to use three MPPTs to monitor and maximize how much power we could get from the solar panels.
We ordered several sample arrays, and tested different methods to access connections and while still protecting the cells from cracking. After countless weeks of research, conversation with manufacturers, and testing, we ordered the panels we intended to put on the car. Due to significant shipping delays posed by the COVID-19 pandemic, the panels did not arrive at our workshop until after quite a few months had passed. Now, we are in the process of building the array that was shipped to us and beginning testing on the solar panels themselves.
One of the key concepts that we have changed in the 2021 solar car from the 2019 one is the blended solar panel. This means that instead of elevating the solar panels above the main frame, we have integrated iot into the top sheet of the car. This means that we must build a frame that both fits at the top of the car, is removable, and capable of holding the solar panels. We have made it our goal to make the majority of this frame out of composite to both save weight and increase the overall strength of the car. We are currently anticipating this process to take a month to complete and are hoping to have a finished car by the end of April.
Building the carbon fiber frame alone will likely take quite a bit of time. Some weeks back, we built a table on which to cut the carbon fiber sheets. Since the manufacturing of this array fram will be mostly out of composites, it will require a lot of patience and waiting around. It is a super delicate job that must be done with precision. The process of joining the parts of the frame itself will look quite similar to the battery box build project we worked on over winter break last year. The carbon fiber sheets will be joined using fiberglass tape and epoxy, each layer of epoxy will take several hours to dry and will need to be sanded in between layers.
After we finish the frame, we will then work on the installation of power leads and bypass diodes on the back surface of the solar panels. We will use a soldering iron to remove the plastic layers that surround the solar cells just enough to access the pre installed connectors for the bypass diodes and output leads. We will have to solder each power lead and bypass diode individually. Once more, not unlike the battery build process of last winter. This process must be done with extreme caution so as not to damage any of the solar cells.
We’re looking forward to better weather and cannot wait to make progress on this project. Time to get moving!