I seem to remember the castaways doing something to recharge the batteries.
Didn't the professor have something where they used coconuts or something?



I remember that episode.
To recharge the batteries the professor soaked them in some sort of citrus or
sal****er solution. I remember asking my father (an electrical engineer) if
this would really work.
I tried it, and it did nothing.
So much for expert fatherly advice.