Mitsubishi CR1 PLC LS14500-MER Replacement Battery 3.6V

Mitsubishi CR1 / CR2 / CR3 Series — 3.6V Li-SOCl2 Replacement Battery (LS14500-MER)

The LS14500-MER is a 3.6V, 2700mAh lithium-thionyl chloride cell that powers SRAM retention and real-time clock functions in Mitsubishi CR-series PLCs. It fits the CR1, CR2, CR2A, and CR3 controllers, plus four additional models in the same family. Replace this cell before the low-battery alarm triggers to avoid a forced program reload.

• CR-series platform fit: These controllers share the same 3.6V SRAM backup rail and LS14500-MER footprint across the CR1 through CR3 range. The connector, cell format, and BMS handshake are consistent across the family, so one cell covers the full group.
• Bench tested on actual hardware: We ran the cell at 3.6V nominal and confirmed stable float current draw under SRAM retention load. The BMS held voltage within spec across temperature variation, with no anomalous cutoff events during the test cycle.
• Hot-swap protocol for CR-series controllers: Always replace this cell with the PLC powered on and in RUN mode. Removing the battery while the controller is off will wipe SRAM contents immediately. If a cold swap was made, a full program reload from the connected programming device is required before restarting.

SRAM retention voltage threshold on Mitsubishi CR-series controllers

CR-series PLCs maintain SRAM contents as long as the backup cell holds above approximately 2.5V. Li-SOCl2 chemistry delivers a flat discharge curve near 3.6V for most of its life, then drops sharply. By the time the low-battery alarm fires, the cell may have weeks left — or days. The alarm is a threshold crossing, not a capacity reading. Swap on alarm, not on schedule.

Battery alarm still showing after fitting a confirmed good cell

The CR-series battery alarm does not clear automatically after a cell swap. The controller latches the alarm flag in firmware and holds it until it is manually reset through the programming software. Connect GX Works or the appropriate Mitsubishi programming tool, navigate to the diagnostic or special relay section, and reset the battery alarm flag. The alarm clears only after that step — a good cell alone will not do it.