This project is for owners of the Capcom CPS2 units who want to change their batteries in a simple and elegant manner. To combat bootleggers, Capcom used encryption in their CPS2 based arcade hardware. The decryption key itself is stored in battery backed RAM. When the battery dies, the game will no longer work since the decryption key has been permanetly lost. At this point, if your battery had died, you would be greeted with an unwelcome solid blue or green screen upon starup. Therefore, it's important to change battery every 5-6 years to prevent the board from commiting suicide.
Changing the battery is straightforward but requires a bit of soldering. A much better method is to mount a battery holder instead. That way the next time you need to change battery, you can do it in 10 seconds (after you have opened the case that is)! I had seen holders for the 1/2 AA batteries before, but it was not until MKL (shmups forum) showed me the Keystone holders with retainers that things became interesting. The retainers prevent the battery from being dislodged!
One 3.6V Lithium battery, size 1/2 AA (Mouser: 667-TL5902S, Elfa part #69-282-12)