Yaskawa MP920 PLC Replacement Battery 3.6V 2400mAh DBA0003

Yaskawa MP920 / MSP-120XC9600 — 3.6V Li-SOCl2 Replacement Battery (DBA0003)

This is a 3.6V lithium thionyl chloride cell rated at 2400mAh, built to the same spec as the Yaskawa DBA0003 and LS14500-YA factory cells. It fits the MP920 and MSP-120XC9600 programmable logic controllers, where it backs up SRAM program memory and the real-time clock during mains power loss. Without a functioning cell, a power interruption wipes the control logic — machinery stops and a full program reload is required.

• MP920 and MSP-120XC9600 compatibility: Both controllers use the same DBA0003 socket, voltage rail, and connector — the cell slots into an identical holder and interfaces with the same memory-backup circuit on both platforms.
• Bench tested on actual hardware: We ran this cell on the MP920 backup circuit and confirmed the BMS accepted the cell without a battery-fault alarm and held SRAM retention voltage above the 3.0V cutoff threshold throughout the test cycle.
• Hot-swap procedure — mandatory for MP920: Always replace this cell with the PLC powered on and in RUN mode. Removing the old cell while the controller is off drains SRAM instantly — the program is gone, and a full reload from the programming device is the only recovery path.

Why the MP920 battery alarm stays active after a confirmed good installation

The MP920 does not automatically clear the battery alarm when a new cell is seated. The alarm is a latched software flag in the controller's system registers, not a live hardware signal that resets on its own. After seating the new cell, you need to clear the alarm manually through the programming software — typically by resetting the relevant system alarm bit or using the ladder monitor to write a reset value to the battery-alarm register. If that step is skipped, the alarm stays on indefinitely even though the cell voltage is correct.

New cell reading below 3.6V on the MP920 system monitor

Li-SOCl2 cells ship in a passivated state — a thin lithium chloride layer forms on the anode during storage, which suppresses open-circuit voltage temporarily. On the MP920's system monitor, this can show as 3.3–3.5V in the first few hours after installation. The cell is not faulty. Once the PLC's float charge circuit works through the passivation layer, voltage climbs back to the rated 3.6V — typically within two to four hours of the controller being powered on. Confirm recovery by checking the battery voltage register again after that window.