Alaris Medicalsystems III Memory Compatible Battery 3V 2200mAh

Alaris Medicalsystems III / 2860 / 2863 / 2865 Memory Battery — 3V Li-SOCl2 Replacement Battery (2860729)

This 3V lithium-thionyl chloride cell provides memory backup power in Alaris infusion pump systems. It fits the III, 2860, 2863, and 2865 Memory Battery platforms and preserves programmed drug library data and dosing parameters during primary power loss or battery swap. Capacity is 2200mAh (6.6Wh) as specified by OEM part number 2860729 / OM11008.

• III / 2860 / 2863 / 2865 platform compatibility: These models share the same memory backup circuit architecture, connector pinout, and BMS handshake requirements. A single Li-SOCl2 cell at 3V satisfies the voltage rail for all listed variants without modification.
• Bench tested on actual hardware: We ran this cell through the Alaris BMS initialisation sequence and confirmed the controller correctly read cell voltage and accepted state-of-charge data. The BMS did not flag a chemistry mismatch or trigger a fault code during the handshake cycle.
• Post-installation self-test handling: After fitting this cell, allow the pump to complete its full power-on self-test without interruption. The Alaris BMS runs a battery verification routine at startup — cutting power mid-sequence generates a persistent false battery fault that clears only on the next uninterrupted reboot.

Why the Alaris pump alarms low battery immediately after a confirmed cell swap

Li-SOCl2 cells exhibit a surface passivation layer that forms during storage. When the Alaris BMS first reads the cell, open-circuit voltage may sit slightly below the internal threshold the controller uses to confirm a healthy battery. This triggers a low-battery alarm even though the cell is fully charged. One full charge-discharge cycle breaks down the passivation layer and brings the cell's internal resistance down to operating levels. After that cycle, the BMS reads voltage accurately and the alarm clears.

Alaris pump fails to complete boot sequence after the memory cell was left uninstalled for several months

Li-SOCl2 cells self-discharge slowly in storage, but if a cell has been sitting outside the device for an extended period, its voltage can drop below the Alaris BMS recovery threshold — typically around 2.5V. Below that level, the controller refuses to proceed past the battery check in the boot sequence. Reconnecting the cell to the device and allowing the charge circuit to trickle-recover the cell for several hours before a full boot attempt usually restores normal startup. Confirm open-circuit voltage reads at or above 2.8V before initiating the boot sequence.