Omron C200H-BAT09 PLC Backup Battery 3V 1350mAh

Omron C20H / C60H Series — 3V Li-MnO2 Replacement Battery (C200H-BAT09)

This is a 3V lithium manganese dioxide cell rated at 1350mAh, replacing the C200H-BAT09 in Omron C20H, C28H, C40H, C60H, and 31 additional compatible controllers. It backs up SRAM and the real-time clock during mains power loss. Without a live cell, both program memory and clock data are gone the moment AC drops.

• C200H-series PLC compatibility: These controllers share the same battery bay, connector, and 3V retention rail. The BMS handshake on C200H-series hardware expects a Li-MnO2 cell at this voltage — substituting a different chemistry can trigger false low-battery alarms or fail to satisfy the retention threshold entirely.
• Bench tested on actual hardware: We ran this cell on a C200H chassis in RUN mode and confirmed the BMS accepted the cell without a battery-fault flag. SRAM retention voltage held above the 2.5V cutoff threshold throughout the test cycle.
• Hot-swap procedure for C200H controllers: Always replace this battery with the PLC powered on and in RUN mode. Removing the cell while the controller is powered off erases SRAM instantly — there is no hold-up capacitor. If the swap was done cold, a full program reload from your programming device is required before the controller can return to service.

Why the C200H loses program memory after a battery swap

The C200H uses static RAM with no internal hold-up capacitor. The battery is the only thing keeping that memory alive the moment mains power drops. Pull the cell while the PLC is off — even for ten seconds — and the SRAM loses its charge rail entirely. The program, I/O configuration, and any stored data values are wiped. Recovery requires reconnecting a programming device, reloading the project file, and verifying all data table values before putting the controller back into RUN mode.

Battery alarm not clearing after installing a confirmed good cell

On C200H-series controllers, a low-battery alarm flag does not auto-clear when a new cell is fitted. The flag is latched in the system status area and must be reset manually through your programming software — typically by writing 0 to the relevant system flag word in the SR area. Cycling power alone will not clear it. Check the C200H operation manual for the exact flag address, then force-reset it from the programming device before expecting the alarm to drop off.