Toshiba ER6VC119A PLC Backup Battery 3.6V 2600mAh

Toshiba ER6VC119A / ER6VC119B — 3.6V Li-MnO2 Replacement Battery (MR-J3 BAT)

This is a 3.6V lithium-manganese dioxide cell rated at 2600mAh, built for PLC backup power applications. It fits Toshiba ER6VC119A, ER6VC119B, and MR-J3 BAT positions — the cells responsible for SRAM memory retention when main power drops. Without a live cell in this slot, your controller loses program data the moment mains power is cut.

• ER6VC119A / ER6VC119B / MR-J3 BAT compatibility: These part numbers share the same AA-format lithium cell form factor, 3.6V nominal voltage rail, and connector footprint. The PLC's BMS draws a float current to monitor cell state — any cell that doesn't hold above the SRAM retention threshold triggers a battery alarm regardless of physical fit.
• Bench tested on actual hardware: We ran this cell under PLC float-charge conditions and confirmed stable voltage above 3.0V — the typical SRAM retention cutoff — across the discharge curve. The BMS handshake cleared without fault codes on connection.
• Hot-swap procedure — mandatory: Always replace this cell with the PLC powered on and in RUN mode. Removing the battery while the controller is off will wipe SRAM immediately. If power was off during swap, the full program must be reloaded from a programming device before the controller can resume operation.

PLC losing program memory after battery swap

SRAM in most PLCs has no capacitor backup — the battery is the only retention source the moment mains power drops. If the old cell was removed while the controller was off, or even briefly disconnected mid-swap without power present, SRAM contents are gone. There is no recovery path from the battery side. The only fix is a full program reload from the programming terminal, followed by verifying all data registers and system parameters before returning the machine to service.

Battery alarm not clearing after a confirmed good installation

A new cell does not automatically clear the battery alarm in most PLC firmware. The alarm flag is latched in software and must be reset manually through the programming software or HMI — the controller will not poll the cell voltage and self-clear. Connect your programming device, navigate to the diagnostic or alarm register, and perform a manual reset. If the alarm returns within seconds, check that the cell voltage has risen above 3.5V — a fresh Li-MnO2 cell shipped at storage voltage can read as low as 3.3V and will climb to full within a few hours on float charge.