Panasonic AFPX-BATT Replacement Battery 3V 550mAh Lithium

Panasonic FP-X Series Controllers — 3V Lithium Replacement Battery (AFPX-BATT)

This 3V, 550mAh lithium cell replaces the backup battery in Panasonic FP-X series programmable logic controllers, GT32, GT32M, and GT32T displays. It holds SRAM program data and keeps the real-time clock running when main power is cut. Without a functioning cell, the controller loses its program and clock the moment mains power drops.

• FP-X series and GT32 display compatibility: These units share the same 3V CR2450-format cell, the same SRAM retention circuit, and the same battery socket — so one part number covers the full range. Voltage tolerance across all these boards is tight: below 2.5V the SRAM retention rail collapses and memory is gone.
• Bench tested on actual hardware: We ran this cell on an FP-X controller and confirmed the BMS accepted the new cell without a fault trip. Float charge settled within the expected range and the battery alarm cleared after a manual reset in the programming software.
• Hot-swap procedure for FP-X controllers: Always replace this cell with the PLC powered on and in RUN mode. Removing the old cell while the controller is off drains SRAM instantly — the program is gone and a full reload from the programming device will be required before the machine runs again.

PLC battery alarm not clearing after a confirmed good installation

On FP-X controllers, the battery alarm flag is set in software and does not clear automatically when a new cell is fitted. The controller detects the voltage has recovered, but the alarm latch stays set until you clear it manually. Open FP-X Configurator or FPWIN Pro, navigate to the system register settings, and reset the battery alarm flag. If the flag is not cleared, the controller will continue reporting a battery fault even with a fully charged cell in the socket.

New cell reading lower than 3V immediately after fitting

Lithium backup cells are shipped at storage voltage — typically 2.7V to 2.85V — to reduce capacity loss in transit. This is normal. Once seated in the controller, the PLC's float charge circuit brings the cell up to its rated 3V within a few hours of the controller being powered. Do not pull and return the cell based on an initial low reading. Check voltage again after four hours on a powered controller — it should read at or above 2.95V.