IBM System x3750 M4 Installation And Service Manual page 109

13. Press the tray retention clip tab outward to release the retention clip that
secures the batteries and flash power modules in the battery/flash power
module trays (on the top of the USB/video assembly near the front of the
server).
Note: If the RAID cache card is installed in the connector on the system
board, place the battery or flash power module in the battery/flash power
module tray slot closest to drive bay 0.
14. Place the battery or flash power module into the battery/flash power module
tray (install the batteries or flash power modules in the trays starting from top
to bottom).
15. Connect the other end of the battery cable or flash power module cable to the
battery or flash power module.
Chapter 2. Installing optional devices
91