Omron JZSP-BA01 PLC Backup Battery 3.6V 1000mAh Li-MnO2

Omron Sigma 2 / SGDH Amplifier — 3.6V Li-MnO2 Replacement Battery (JZSP-BA01)

This is a 3.6V, 1000mAh lithium manganese dioxide backup cell for the Omron Sigma 2, Sigma II, SGDH amplifier, and Sigma II/V Servo Driver series. It maintains SRAM program memory and the real-time clock when main power is removed. Without a functioning cell, both the ladder logic and timestamp data are lost the moment mains power drops.

• Sigma 2 and SGDH platform fit: These drives share the same 3.6V backup rail, JZSP-BA01 connector footprint, and BMS handshake protocol — one cell covers the full range listed above without modification.
• Bench tested on actual hardware: We seated the cell in an SGDH amplifier under load and monitored the backup rail. The BMS accepted the cell immediately, voltage held at 3.6V across the SRAM retention circuit, and the clock register stayed intact through a simulated mains dropout.
• Hot-swap procedure for this drive: Always replace this cell with the servo driver powered on and in RUN mode. Removing the depleted cell while power is off clears SRAM instantly — the program is gone. If the swap happened during a power-off, a full program reload from the programming device is required before the drive can operate.

Why the Sigma 2 battery alarm persists after a confirmed good installation

On the SGDH and Sigma II platform, the battery alarm flag is latched in the drive's parameter memory — it does not clear automatically when a fresh cell is detected. After seating the new JZSP-BA01, the alarm must be manually reset through the programming software or the drive's parameter write function. Cycling power alone will not clear it. Navigate to the battery alarm reset parameter in SigmaWin+ and execute the write command to clear the fault flag.

New cell reading below 3.6V on the SGDH backup rail

Li-MnO2 cells ship at a storage voltage typically between 3.2V and 3.4V — this is normal for long shelf stock and not a sign of a defective cell. The SGDH float charge circuit will bring the cell up to its rated 3.6V within a few hours of the drive being energised. Do not swap the cell again based on an initial low reading. Re-check the backup rail voltage after four hours of powered operation — it should read at or above 3.55V.