Regal LS4 Owner's Manual page 114

To remove the bottom battery we recommend
removing the top battery sliding tray from the sliding
channels to afford easier access.
Next, remove battery terminal hardware and stud
hold down hardware to allow removal from tray.
Lift the battery safely out of the tray. Make sure the
battery remains positioned with the battery caps
facing up to prevent electrolyte spillage. See photo
below.
Note that the battery box hold down studs can be
removed as needed by turning counterclockwise.
BATTERY CABLE (-)
STACKED BATTERY SYSTEM-TYPICAL
LATCH
SLIDING TRAY
HOLD DOWN
BATTERY BOOT (+)
STUD/HDWR.
BATTERY CABLE (+)
LATCH
114