Saft LS14250 Replacement/Upgrade Solution for LS Series

Product Overview

Saft LS14250 Replacement/Upgrade Solution for LS Series: Seamless Transition for Legacy PLC Memory Backup Systems

The Saft LS14250 is a 3.6V 1/2AA Lithium Thionyl Chloride (Li-SOCl₂) primary battery engineered for long-term, maintenance-free memory backup in industrial programmable logic controllers, distributed control systems, and embedded automation hardware. As legacy PLC platforms age and original battery stocks become harder to source, the LS14250 remains the definitive drop-in replacement for a wide range of discontinued and end-of-life memory backup cells used across Siemens SIMATIC S5 and S7 series, Mitsubishi MELSEC Q and FX series, Omron CJ and CS series, Schneider Electric Modicon M340 and Premium series, and Allen-Bradley MicroLogix and SLC 500 platforms.

For maintenance engineers managing aging control infrastructure, the LS14250 eliminates the risk of SRAM data loss, program corruption, and unplanned downtime caused by depleted backup cells. Its ultra-low self-discharge rate — less than 1% per year — ensures reliable data retention across multi-year service intervals, making it the preferred choice for facilities operating on extended preventive maintenance cycles.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful PLC memory backup battery replacement is rarely a standalone task — it is part of a broader system health check and, in many cases, a planned migration from aging hardware to a more maintainable control architecture. When replacing the LS14250 in a Siemens SIMATIC S7-300 CPU module such as the CPU 315-2 DP or CPU 317-2 PN/DP, engineers typically perform a full program backup via the Siemens MPI programming cable or PROFIBUS DP communication module before powering down the rack. This ensures that the user program stored in the CPU’s internal SRAM is preserved independently of the battery.

For installations using a Siemens S7-300 power supply module (PS 307 5A or PS 307 10A), verifying the 24VDC rail stability before and after battery replacement is a recommended step, as voltage fluctuations during the swap window can corrupt retentive data areas. In distributed I/O architectures using ET 200M remote I/O stations or IM 153 interface modules, the battery replacement procedure on the central CPU does not affect the remote I/O nodes, but the system should be placed in STOP mode to prevent unintended output activation during the maintenance window.

Facilities migrating from Siemens S5-115U or S5-135U platforms — where the original Saft LS14250 or equivalent was used in the CPU 941 or CPU 944 modules — to modern S7-1500 or S7-1200 controllers will find that the LS14250 remains relevant during the transition period, as the legacy CPUs must remain operational until the new program is validated and cut over. During this parallel-run phase, a fresh LS14250 in the S5 CPU ensures data integrity without requiring an emergency shutdown.

In Mitsubishi MELSEC Q series systems, the Q02CPU and Q06HCPU modules use a similar 1/2AA 3.6V Li-SOCl₂ cell for program and device memory retention. The LS14250 is a confirmed compatible replacement, and the swap procedure mirrors the Siemens workflow: backup via GX Works2 or GX Developer over USB or Ethernet, power down, replace cell, restore, and verify. For Omron CJ2M and CS1G CPU units, the battery replacement procedure is documented in the hardware manual and requires no special tools beyond a small flat-head screwdriver to release the battery holder clip.

When the replacement is part of a broader control cabinet retrofit — for example, integrating a new Siemens SINAMICS G120 variable frequency drive alongside the existing PLC rack — the battery swap should be scheduled as part of the cabinet shutdown window to minimize total downtime. Similarly, if the retrofit includes adding a CP 343-1 Ethernet communication processor to an existing S7-300 rack, the CPU battery should be replaced at the same time to reset the maintenance clock on all consumable components.

Retrofit Guidance FAQ

Q: Can I replace the LS14250 while the PLC is powered on (hot-swap)?
A: This depends on the CPU model. Most Siemens S7-300 CPUs support a brief hot-swap window (typically under 30 seconds) without data loss, as the CPU uses a capacitor to bridge the gap. However, for safety and data integrity, TOPNLMS recommends performing a full program backup before any battery replacement, regardless of the CPU’s hot-swap capability.

Q: What happens to my PROFIBUS or PROFINET configuration if the battery dies?
A: The communication configuration stored in the CPU’s load memory (Flash) is retained without battery power. Only the retentive data areas (M, DB, T, C) stored in SRAM are at risk. A depleted battery will not affect your network topology or I/O mapping, but it will cause loss of retentive process values on the next power cycle.

Q: Is the LS14250 compatible with DIN rail-mounted battery holders used in control cabinets?
A: Yes. The standard 1/2AA form factor is compatible with all common DIN rail battery holder accessories. If your installation uses a remote battery holder connected to the CPU via a cable assembly, the LS14250 fits directly without modification.

Q: How do I know when the battery needs replacement?
A: Most PLCs provide a battery low diagnostic alarm via the CPU’s status LED or a system diagnostic block (OB81 in Siemens S7). TOPNLMS recommends proactive replacement every 3–5 years regardless of alarm status, as the alarm threshold is typically set conservatively and the remaining service life after the alarm may be limited under high-temperature conditions.

Q: Can the LS14250 replace the LS14250C (with connector)?
A: The LS14250C is a connector-terminated variant of the same cell. If your CPU uses a connector-type battery, you will need to either source the LS14250C specifically or use a compatible adapter harness. Contact TOPNLMS for connector-terminated variants or custom cable assemblies.

Q: What is the shelf life of the LS14250?
A: Saft specifies a 10-year shelf life for the LS14250 when stored at room temperature. TOPNLMS ships only fresh stock with full remaining shelf life, and each shipment includes a date code for traceability.

Warranty Assurance

Every Saft LS14250 shipped by TOPNLMS is covered by a 12-month replacement warranty from the date of delivery. Prior to shipment, each battery lot undergoes open-circuit voltage verification and visual inspection to confirm cell integrity. Batteries showing voltage below 3.5V or any signs of electrolyte leakage are quarantined and not shipped.

In the event of a warranty claim, TOPNLMS provides a direct replacement without requiring the customer to return the defective unit for laboratory analysis — a critical advantage for facilities where downtime costs far exceed the unit price of the battery. Warranty replacements are dispatched within 2 business days of claim confirmation.

For bulk procurement — common among system integrators, OEM panel builders, and MRO distributors — TOPNLMS offers volume pricing, consolidated shipment, and extended payment terms. All orders include a packing list with individual date codes, enabling full traceability for ISO 9001-compliant maintenance records.

Shipping is available worldwide from our Xiamen warehouse, with DHL Express, FedEx International Priority, and sea freight options depending on order volume and urgency. Typical transit time to Europe and North America is 3–7 business days via express courier.