A water powered pendulum pulse light. https://www.youtube.com/watch?v=VzVurIxWqow (https://www.youtube.com/watch?v=VzVurIxWqow)
https://www.youtube.com/watch?v=64EDo4OB_L0
This is remarkable, but why nobody came up with this idea before?
These batteries were around for around three hundred years, weren't they?
How many watts your setup generates?