Cutler Hammer Fanuc 90-30 PLC Compatible Battery 3V 1800mAh

Cutler Hammer Fanuc 90-30 PLC — 3V Li-MnO2 Replacement Battery (A02B-0118-K111)

This is a 3V lithium-manganese dioxide cell rated at 1800mAh (5.4Wh), sized to replace the backup battery in the Fanuc 90-30 PLC. It maintains SRAM program memory and the real-time clock whenever mains power is removed. Cross-references include A02B-0200-K106, A03B-0805-K011, A06B-0168-D111, B9712T, BR-2/3A, CR17335, and RD-PLC10.

• Fanuc 90-30 series fit: The 90-30 controller uses a single 3V lithium cell to hold SRAM contents and keep the RTC ticking during power-off events. All cross-referenced part numbers above share the same cell format, voltage rail, and connector footprint used across this PLC family.
• Bench tested on actual hardware: We ran this cell against a 90-30 backplane under load cycling. The BMS held steady voltage through repeated power-cycle events, and SRAM retention remained intact across all test sequences without memory fault flags.
• Hot-swap protocol for the 90-30: Always replace this battery with the PLC powered on and in RUN mode. Removing the cell while the controller is powered off drains SRAM instantly — the program is gone and must be reloaded from a programming device. No power cycle happens between pull and insert.

PLC losing program memory after battery swap

The 90-30 uses battery-backed SRAM with no secondary retention capacitor. The moment battery voltage drops below the SRAM hold threshold — roughly 2.0V — memory content is lost. This happens in seconds if the cell is pulled while the controller is off. If the program is gone after a swap, the only fix is a full reload from the programming terminal using the last saved ladder logic backup.

Battery alarm not clearing after a confirmed good cell installation

The 90-30 controller latches the low-battery alarm in firmware — it does not clear automatically when a new cell is installed. After fitting the new battery, the fault must be manually acknowledged and reset through the programming software. Navigate to the fault table in the PLC software, clear the battery alarm entry, and confirm the status word returns to 0x00 before closing the session.