Dell PowerEdge C8220 Hardware Owner's Manual page 170

Figure 3-20. Removing and Installing the RAID Battery Assembly
1
1 M3 screws (2)
3 RAID controller card
6 Pry one end of the RAID battery and pull the battery straight out of the
battery holder. See Figure 3-21.
170
Installing System Components
2
2
4
3
RAID battery assembly
RAID battery cable
4