[theiz]

Of all this amazing stuff, I learned today they were considering using solar panels on a zeppelin in 1936. I really though solar panels were from the 1980’s onwards.

[NikkiA]

1876 for selenium based solar cells.

https://en.wikipedia.org/wiki/Selenium#Solar_cells

Silicon solar cells are/were massively more effective, and came to light just before their popularization in the space race.