A 1500 Rack mount power supplies contain batteries that provide a continuous power source to the computer systems connected to them (most likely a server bank), so that should a building's power fail the computers will still be able to function. If the batteries in the 1500 fail, the power supply won't work, leaving the computers vulnerable. Replacing the batteries in a 1500 Rack mount takes about 30 minutes.
1). Look on the front of the 1500 mounted in the rack and locate the battery pack cover, on the right side of the assembly. Using a screwdriver, take off the screws holding the cover to the assembly. Place the cover and the screws in a safe place.
2). Unscrew the interior panel on the battery pack from the case. Put the interior panel and the screw in a safe place as well. Unplug the battery pack from the 1500 by unplugging the harness.
3). Slide the battery tray out of the rack, making sure not to touch any of the terminals on the batteries with your hands. Put the replacement battery tray into the 1500, sliding it carefully in place while keeping the battery harness from getting pinched by the tray. Plug in the replacement battery pack assembly to the stock harness.
4). Reinstall the interior panel on the 1500 using the screwdriver. Reinstall the outer cover.