Baghdad battery

A term used by G.I.s, specifically those operating in Iraq, for standard issue batteries designated for use in their night vision goggles. The batteries are often removed from their night vision goggles, which are of no use during daytime or in non-combat settings, and used to power other battery operated devices, standard issue or not.

"Roger, if you don't stop playing gameboy, you're gonna kill your Baghdad battery. Then you'll be in some serious trouble come nightfall."