DC single wire – 50ft from solar
Because of the ability to keep the voltage output but current is reduced, it stood to reason that a low current system would work.
In this video, I show how both the 12V car battery and a very easily replicable half dozen solar panels setup produce good LED lighting to at least 50ft distance over 1 wire.
The other connection, the Negative of the solar or battery output goes straight into the ground.
(distance measured a few years ago from the back door to the shed as 55ft, for model glider aircraft tests. The tree is approx 6ft to the left and 3ft in front of the door)