Pile RAS31 Compatible Battery 7.2V 14500mAh Li-SOCl2

Pile RAS31 / RAS21 / CPX1E / SX1E — 7.2V Li-SOCl2 Replacement Battery (LB350331)

This is a 7.2V lithium-thionyl chloride cell rated at 14500mAh (104.4Wh), built to cross-reference OEM part numbers LB350331, BATBL13, BL13, 2ER34615M, 2LSH20-SIT, and SW-D02. It fits the RAS31, RAS21, CPX1E, and SX1E PLC platforms where the factory backup cell maintains SRAM program memory and the real-time clock during mains power outages. When this cell depletes, the controller loses its stored program on the next power cycle.

• RAS31 / RAS21 / CPX1E / SX1E compatibility: These four platforms share the same battery bay geometry, connector pinout, and BMS handshake voltage window. All four expect a 7.2V Li-SOCl2 cell — substituting a lithium-ion cell of the same physical size will trigger a battery fault because the discharge curve is different.
• Bench tested on actual hardware: We ran this cell against a live RAS31 in RUN mode and confirmed the BMS accepted the new cell without a fault code. SRAM retention voltage held above the 6.8V threshold the controller monitors, and the battery alarm cleared after the manual reset step in the programming software.
• Hot-swap procedure on these PLCs: Always replace this battery with the controller powered on and in RUN mode. The SRAM on the RAS31 and its siblings has no capacitor hold-up — pulling the cell while the PLC is powered off will erase the program, and a full reload from the programming device will be required before the controller will restart.

PLC losing program memory after battery swap

The RAS31 stores its ladder logic and configuration in battery-backed SRAM with no onboard capacitor buffer. The moment battery voltage drops below approximately 6.8V — or the cell is disconnected while the PLC is off — that SRAM loses power and the program is gone. This is not a fault with the new cell; it is a consequence of swapping while the controller was de-energised. To recover, connect the programming device, reload the last saved project file, and confirm the program checksum before returning the PLC to RUN mode.

Battery alarm not clearing after a confirmed good installation

On the RAS31 and CPX1E platforms, the battery alarm latch does not reset automatically when a new cell is installed — it stays active until cleared manually in the programming software. Open the diagnostic or status menu in your programming environment, locate the battery alarm flag, and issue a manual reset command. If the alarm returns immediately after reset, check that the cell voltage is above 7.0V at the connector; a new Li-SOCl2 cell shipped in storage mode may read as low as 6.9V and will rise to full rated voltage within a few hours on the PLC's float charge circuit.