You would be amazed at how little power a solar panel gets in the classroom or the lab.
I measure it. It is one half of one percent of full sun (0.5%). Practically nothing. Here are two examples:
1) We have a flight unit of the original TRANSIT satellite in our sun lit wall-of-glass lobby. It has about 8000 1 inch square solar cells. We built a small "packet" link and a small SSTV camera so we could command it and watch when refreshments were being served in the lobby. Even with all those solar cells, and full indoor lighting and indirect window lighting, the power available is only about 0.1 watt. We had to back off and only have it come on when there was full sun on the arrays in the late afternoon, all the other time there was no power to run it. Even with the eight 1'x6'solar panels.
2) Laugh at this one and BUYER BEWARE! check out www.solaroadtechnologies.com. They claim "Their products are undoubtedly the best solar/storage products available." They are located in Towson, Maryland. And complete hogwash. They sell you solar panels for your desk and your cubical to collect free energy from the office lighting. Yes, not even enough to light a single LED. 0.5% of outdoor sun is nothing.
Modern day adage: Just because there is light, and just because it spins, does not mean there is any useful power!
Bob, WB4APR