He wants to do this expermiment w/ a very old dead battery.

The assumpution is, " that can a very old, very dead battery have enough potential to radiate a broadband signal across the frequency spectrum and signal someone or something."

Micro volt signals can radiate very far, maybe into the cosmos. Detection is another matter, and I dont think there are little green men trying to listen. As for exploding in your face w/ a very dead battery, I dont think so.