A guard who refills ATMs for a living learned a valuable lesson Friday afternoon when he left his armored cash van parked outside a building in Battery Park — and it got towed.

The hapless driver discovered the Shields Business Solutions vehicle missing outside 1 Battery Park Plaza about 20 minutes later after leaving it illegally parked, sources said.

Police ordered the vehicle towed because it was parked in a zone reserved for filming of the CBS show “Elementary.”

The driver retrieved his van from an impound lot in Midtown and billed his company for the summons and tow fee.