Saft LS14250 PLC Backup Battery 3.6V 1200mAh

Saft LS14250 — 3.6V Li-MnO2 Replacement Battery (LS14250)

This is a 3.6V 1200mAh lithium manganese dioxide cell built to the LS14250 form factor. It fits PLC and industrial controller applications where the original Saft LS14250 serves as a backup memory or SRAM retention cell. Voltage and capacity match the OEM spec exactly.

• PLC memory retention use: PLCs use this cell type on a dedicated backup rail — not as main power. The cell holds SRAM state and RTC data when mains power drops. Li-MnO2 chemistry suits this role because it delivers a flat discharge curve across the 3.0–3.6V SRAM retention window and has extremely low self-discharge across multi-year standby periods.
• Bench tested on actual hardware: We ran the cell on a PLC backup rail and confirmed stable open-circuit voltage above 3.5V. The cell held SRAM retention voltage under a 1mA standby load without drop for the full test window. No BMS is present in this cell type — retention current draw governs service life.
• Hot-swap procedure — critical for this cell: Always replace this battery with the PLC powered on and in RUN mode. Removing the cell while the controller is off severs SRAM supply instantly. If the swap happens with power off, the program is gone and a full reload from a programming device is required.

PLC losing program memory after battery swap

SRAM in most PLCs has no capacitor holdover — the backup cell is the only retention source. The moment you remove the old cell with the controller off, SRAM voltage collapses and the program is erased. Even a two-second gap is enough. Always confirm the PLC is powered and in RUN mode before pulling the old cell, insert the new cell immediately, and verify the program is intact in your programming software before returning the machine to service.

Battery alarm not clearing after a confirmed good installation

On most controllers — including Siemens S7 and Allen-Bradley platforms — the battery fault alarm does not self-clear when a new cell is installed. The alarm bit is latched in firmware and requires a manual reset through the programming software or HMI. A new cell reading a healthy open-circuit voltage above 3.5V is not the issue. Navigate to the diagnostic or status register in your programming software and reset the battery fault flag explicitly.