Yaskawa Motoman 3.6V PLC Backup Battery 479348-1

Yaskawa Motoman Robot — 3.6V Li-MnO2 Replacement Battery (479348-1)

This 3.6V, 2000mAh lithium manganese dioxide cell replaces OEM part 479348-1 in Yaskawa Motoman robotic controllers. It backs up SRAM program memory and the real-time clock during main power interruptions. Swap it before the controller logs a low-battery alarm to avoid a full program reload.

• Motoman controller compatibility: Yaskawa Motoman controllers route backup power through a dedicated 3.6V rail that feeds the SRAM module and RTC simultaneously. A cell outside the correct voltage window or with an incompatible footprint will fail the BMS handshake and trigger an immediate battery fault — this cell matches the OEM dimensions (51.10 × 16.40 × 14.70 mm) and voltage profile exactly.
• Bench tested on actual hardware: We ran this cell under simulated SRAM retention load at 3.6V nominal. The cell held above the 3.0V SRAM retention threshold throughout the discharge curve, and the BMS accepted it without generating a spurious alarm on reconnection.
• Hot-swap procedure — mandatory: Always replace this cell with the Motoman controller powered on and in RUN mode. Removing the battery while the controller is off drains SRAM instantly. If the controller was off during the swap, reconnect power and reload the robot program from your programming pendant or backup media before resuming production.

Why the Motoman controller loses its program after a battery swap

SRAM in Motoman controllers is volatile — it requires continuous voltage above approximately 3.0V to retain data. When the battery is removed with the controller powered off, the SRAM loses that supply within seconds and the entire program is erased. This is not a fault with the replacement cell — it is a consequence of the swap sequence. Always power the controller on before disconnecting the old cell, then fit the new one while power is live. This keeps the SRAM supply uninterrupted through the swap.

Battery alarm still showing after confirmed good installation

Motoman controllers do not auto-clear a battery alarm once a new cell is fitted — the alarm flag is written to a register that requires a manual reset. After installing the replacement, navigate to the alarm history on the programming pendant and clear the battery alarm entry directly. If the alarm reappears within 24 hours, check cell voltage at the connector: a fresh Li-MnO2 cell ships at storage voltage, typically 3.4–3.5V, and rises to nominal 3.6V within a few hours on float charge. An alarm that persists past that window indicates a wiring or contact fault at the battery holder.