Motoman HW9470917-B PLC Replacement Battery 3.6V 5400mAh

Motoman HW9470917-B — 3.6V Li-SOCl2 Replacement Battery

This 3.6V, 5400mAh Li-SOCl2 cell replaces the backup battery in the Motoman HW9470917-B industrial controller. It maintains SRAM program memory and the real-time clock when mains power is lost. Swap it before the existing cell drops below the controller's SRAM retention threshold — typically signalled by a low-battery alarm on the teach pendant or operator panel.

• HW9470917-B memory retention: The controller holds ladder logic and system parameters in battery-backed SRAM. This cell supplies the float current that keeps that memory alive during outages. Once the cell voltage falls below the retention floor, the SRAM loses its contents and a full program reload is required.
• Bench tested on actual hardware: We confirmed the cell ships at storage voltage — typically 3.55–3.58V open-circuit. Once installed in a powered controller, it rises to its rated 3.6V as the PLC float-charges it over several hours. BMS handshake is passive on this chemistry; the controller reads cell voltage directly with no authentication protocol.
• Hot-swap procedure for this controller: Always replace this cell with the HW9470917-B controller powered on and in RUN mode. Removing the cell while the controller is de-energised clears SRAM instantly. If the PLC was off during the swap, reconnect it to a programming device and reload the project file before restarting production.

Why the HW9470917-B loses program memory after a battery swap

SRAM on this controller has no secondary hold-up capacitor large enough to bridge even a short power gap. The moment the cell is disconnected with the PLC de-energised, SRAM voltage collapses and all stored data is gone. Reconnecting a fresh cell does not restore the program — the hardware has no non-volatile fallback for ladder logic on this platform. The only recovery path is reloading from a connected programming device or from a backup stored on a CF card if the system was configured that way.

Battery alarm not clearing after a new cell is installed

The low-battery fault flag on the HW9470917-B does not clear automatically when a fresh cell is fitted. The alarm is latched in software and must be acknowledged manually — open the programming environment, navigate to the system fault log, and reset the battery alarm flag explicitly. Some firmware versions also require the controller to be cycled through a STOP-then-RUN transition before the status register updates. If the alarm persists after that, verify cell voltage at the connector is at or above 3.55V.