We have been working on the solar top for the Lunar Rover. The rover will use six 15.4V PowerFilm solar panels (PT15-300) to generate a total of 1.2 Amps @ 15.4V, which will be used to charge the 3-cell 12V lithium-ion battery. Each panel is 10.6″ x 12.8″. We selected the PowerFilm panels because they were thin, flexible, rugged, easy to work with, and came in a variety of shapes and sizes. We mounted the panels in between a sandwich of custom-designed, CNC-machined carbon fiber plates that we designed for the purpose. We used carbon fiber (provided by DragonPlate) because it was lightweight and rigid. The plates are held together with small, black, #2-56 screws. Because we wanted the area between the plates to be thin, we didn’t use our normal 24 AWG wire, which was too thick. Instead, we used copper conductive strip, which is flat. When mounted on the robot, two of the panels will be in the central, fixed position. There will also be a pair of panels on “solar wings” on each side. The wings will start out folded on top of the robot’s main body over the two fixed panels. When we want to deploy the solar wings, small motors will open them up like the pedals of a flower, exposing all six panels to the sun. This design allows us to keep the robot compact for transport, but have three times the surface area and therefore three times the current for charging the batteries.
Friday, April 29th, 2016