TL;DR

The CompactLogix 5380 battery alarm is straightforward: order the correct lithium battery, replace it with the controller powered on to preserve memory, and acknowledge the alarm. The battery typically lasts 5 to 7 years.

What you might see

battery LED on the controller face flashing amber
Studio 5000 controller properties shows battery low status
battery low fault in the controller fault log
battery has not been replaced in more than 5 years

Likely causes

Tap to mark as ruled out

Lithium backup battery reaching end-of-life after 5 to 7 years of service
Controller power cycled frequently, increasing battery drain from unplanned power-off events
High ambient temperature accelerating battery self-discharge

Required tools

Replacement lithium battery (Rockwell-approved catalog number for 5380)
Small flathead screwdriver (for battery door if required)

Safety first

Replace the battery with the controller powered on. Replacing with power off risks program loss if no backup SD card is in place.
Do not short-circuit or incinerate the lithium battery. Dispose of it as hazardous waste per your facility's procedure.

Procedure

8 steps · ~15 min

1
Order the replacement battery by the Rockwell catalog number shown on the existing battery or in the CompactLogix 5380 User Manual. Do not substitute a generic battery.[1]
2
Confirm the controller is powered on before replacing the battery. Replacing the battery with power off will erase the program if no SD card or nonvolatile memory backup exists.[1]
3
Open the controller battery door on the front of the controller module. The door is typically a small hinged cover on the bottom-left of the module face.
4
Note the polarity of the existing battery before removing it.
5
Remove the old battery and immediately insert the new battery with correct polarity. Do not leave the battery socket empty for more than 30 seconds while the controller is powered.[1]
6
Close the battery door.
7
Confirm in Studio 5000 (Controller Properties, General tab) that the battery status has cleared. The amber LED should go out within a few minutes.
8
Dispose of the old lithium battery per your facility hazardous waste procedure.

Sources

Allen-Bradley CompactLogix 5380 Controllers User Manual (Pub 5069-UM001), Rockwell Automation (Allen-Bradley)
Allen-Bradley CompactLogix 5380 Controllers User Manual, battery replacement procedure and part number (general)
View source

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