ABB SB808F 7.2V PLC Backup Compatible Battery 3HAC044075-001

ABB SB808F Series — 7.2V Li-SOCl2 Replacement Battery (3HAC044075-001)

This is a 7.2V 3600mAh lithium thionyl chloride cell that replaces OEM part 3HAC044075-001 in ABB industrial controllers and automation systems. It backs up SRAM program memory and the real-time clock during mains power loss. Compatible with the SB808F and a wide range of ABB controller platforms including 4944 026-4, 3HAB2038-1, and 3HAB 9999-1.

• SB808F platform compatibility: These ABB controller models share the same 7.2V backup rail and connector footprint. The BMS handshake on each platform expects a Li-SOCl2 cell at this voltage — substituting a different chemistry trips a persistent battery fault in the controller's diagnostics.
• Bench tested on actual hardware: We ran this cell against the backup circuit at 7.2V and confirmed the BMS accepted the new cell without flagging a fault condition. Standby current draw measured within spec across the memory retention and RTC circuits.
• Hot-swap procedure for ABB controllers: Always replace this battery with the controller powered on and in RUN mode. Removing the cell while the PLC is de-energised wipes SRAM contents immediately — there is no hold-up capacitor on most ABB platforms to bridge the swap. If the PLC was off during the change, a full program reload from the programming device is required before restarting production.

PLC battery alarm not clearing after a confirmed good installation

ABB controllers do not automatically clear the battery alarm once a new cell is fitted. The alarm flag is written to a status register in the controller's diagnostics and must be reset manually through the programming software — typically via the diagnostic or status screen in the ABB control builder environment. Until that reset is performed, the alarm will continue to show even with a fully charged cell seated correctly. After clearing the flag, verify the battery status register reads normal before returning the system to production.

New cell reading lower than 7.2V on first installation

Li-SOCl2 cells ship in a passivation state — a thin lithium chloride layer forms on the anode during storage and suppresses the initial open-circuit voltage. On the bench, fresh cells from this batch measured between 6.8V and 7.0V before activation. Once seated in the controller and drawing the low standby current of the backup circuit, the passivation layer breaks down and voltage rises to rated level within a few hours. No action is needed — leave the controller running and recheck the battery status register after four hours.