Servo Controller PLC AB Allen Bradley 1769-BA Battery Assembly Custom

Allen-Bradley 1769-BA | CompactLogix 3V Lithium Battery Assembly — 850 mAh / Memory Retention / 1769-L23x / L3x

The Battery That Keeps the Programme When the Power Goes

A CompactLogix controller stores its user programme and data memory in battery-backed SRAM. When the power supply is disconnected or fails, the 1769-BA lithium cell takes over, maintaining the programme intact for the duration of its charge. When the battery is absent or depleted, a power interruption — even a brief outage — causes the controller to lose its user programme. The machine returns to an uninitialised state and will not restart until the programme is reloaded.

The 1769-BA is a lithium non-rechargeable cell in a pre-wired housing with a 3-pin connector. It installs directly in the battery compartment on the CompactLogix controller body. The BAT LED on the controller illuminates when the battery charge nears depletion — this is the replacement indicator. Do not wait until the LED activates and then leave the replacement delayed; a significant discharge has already occurred by the time the BAT warning appears.

Key Specifications

Replacement Procedure — Keep Controller Powered

Replace the 1769-BA with the controller powered on wherever possible. With power applied, the controller's internal capacitors briefly maintain the SRAM while the battery is swapped. Replacing with the controller de-energised risks data loss if the capacitor charge is insufficient to bridge the swap time. Work quickly — connect the new battery before disconnecting the old one if the controller layout permits parallel connection during the changeover.

The 1769-BA is the battery specified for 1769-series CompactLogix controllers. It is not interchangeable with 1747-BA (which serves the SLC 500 family) or other Allen-Bradley battery types — confirm the part number before installation.

FAQ

Q1: How long does the 1769-BA last in service?

Typical service life is 3–5 years under normal conditions, though operating temperature significantly affects longevity — elevated ambient temperatures shorten battery life. Replace at or before 3 years in continuous production environments, or immediately when the BAT LED activates on the controller.

Q2: The BAT LED is on. How urgent is replacement?

Replace promptly — within days, not weeks. The BAT LED indicates the battery has already discharged to a low threshold. Some remaining capacity exists at the time the LED activates, but continued delay risks reaching zero charge. A power interruption with a fully depleted battery causes immediate programme loss.

Q3: Can the controller run normally without a battery?

Yes — the controller runs normally with a depleted or absent battery as long as power is continuously applied. The battery only matters during a power interruption. Without a battery, any power cycle (planned or accidental) will clear the user programme from SRAM.

Q4: Is the 1769-BA interchangeable with the 1747-BA?

No. The 1747-BA is specified for the SLC 500 controller family. The 1769-BA is for CompactLogix. The two are different form factors with different connectors. Using the wrong battery type for the platform may cause improper seating, incorrect voltage, or unreliable memory backup. Confirm the part number matches the installed controller's battery compartment specification.

Q5: How should used 1769-BA batteries be disposed of?

Lithium batteries must not be disposed of in general waste. Follow local regulations for lithium battery disposal — most municipalities and industrial sites have lithium battery recycling or disposal programmes. Do not incinerate, puncture, or short-circuit a used lithium cell.