Thread:Loconator3000/@comment-5688420-20190604075553/@comment-5688420-20190609205203

A battery located in the arcade board itself that contains important encryption keys to play games. If this battery runs out, the unit may never work again, hence "suicide battery".

It was first used by Sega for their System 16 arcade board (the later System 18 and X-Board also use the suicide battery), but was largely infamous for being used in Capcom's CPS2 arcade board.