RepairXpert Industrial Automation

Allen-Bradley PLC Minor Fault — Battery Low (Type 10)

AB-PLC-MINOR10

ControlLogix or CompactLogix processor reports low backup battery. Battery maintains the real-time clock and may be needed for energy storage module backup on older controllers.

low allen-bradley conveyor packaging palletizer piler asrs
allen-bradley plc controllogix compactlogix minor fault battery 1756-BA2 1769-BA

Probable Causes (ranked)

Fix Steps

  1. 1 Replace battery with controller powered ON — CompactLogix uses 1769-BA, ControlLogix uses 1756-BA2
  2. 2 For ControlLogix: battery is in the CPU module — slide open the battery door, swap battery, close door
  3. 3 For CompactLogix 5370/5380: battery is in a holder on the side of the controller
  4. 4 After replacement, verify BATTOK status LED is green or battery fault clears in RSLogix
  5. 5 Note: CompactLogix 5480 and newer ControlLogix 5580 use non-volatile memory and do not require batteries
  6. 6 Record battery change date on a label inside the panel door

Field Trick

Even though modern Logix controllers save programs to non-volatile memory, the battery still powers the real-time clock. If the clock matters for data logging or shift tracking, replace the battery promptly.

Suggested Replacement Parts

Parts matched to fault category: Plc Battery

Allen-Bradley 1756-BA2 PLC Battery P/N: 1756-BA2 ControlLogix battery module, 3V lithium, 2-year life
AutomationDirect $22.00 Amazon $18.00 Grainger $28.00
Mitsubishi Q6BAT PLC Battery P/N: Q6BAT MELSEC-Q series, 3.6V lithium, ER17330V
Amazon $12.00 Digikey $15.00 AutomationDirect $14.00
Siemens 6ES7971-0BA02 PLC Battery P/N: 6ES7971-0BA02 S7-300/400 backup battery, 3.6V lithium AA
Amazon $15.00 Mouser $18.00

Prices are estimates. Verify part numbers match your equipment before ordering.

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