About this replacement
ABB Robotics 4944 026-005 — 3.6V Li-SOCl2 Replacement Battery
This is a 3.6V, 14500mAh Li-SOCl2 cell that replaces ABB Robotics part number 4944 026-005. It fits ABB Robotics PLC systems where the battery maintains SRAM program memory and real-time clock function during power outages or planned maintenance. Without a live cell in this slot, the controller loses its program the moment mains power drops.
- ABB Robotics PLC memory retention: These controllers rely on a continuous low-drain float from this cell to hold SRAM state and RTC data. The Li-SOCl2 chemistry delivers a stable 3.6V discharge curve over years of standby draw, which is exactly what the memory retention circuit requires — a flat voltage profile rather than the sloping curve of alkaline or standard lithium cells.
- Bench tested on actual hardware: We ran this cell under a simulated PLC standby load and confirmed the BMS delivers stable output from full charge down through the low-voltage cutoff range. Voltage held within spec across the test window with no dropout events.
- Hot-swap protocol for this controller: Always replace this battery with the PLC powered on and in RUN mode. Removing the cell while the controller is off will erase SRAM — the program stored in volatile memory will be gone and must be reloaded from a programming device. Never power down first, then swap.
PLC losing program memory after battery swap
This is the most destructive mistake made during ABB PLC battery replacement. The SRAM holding the controller program is volatile — it needs continuous voltage to retain data. If the old cell is pulled while the PLC is off, or if the swap takes long enough for voltage to collapse, the memory contents are lost. A new cell in the slot will not restore what was erased. The only recovery is a full program reload from the original project file using the programming software.
Battery alarm not clearing after confirmed good installation
Fitting a new cell does not automatically clear the low-battery alarm flag on ABB PLC systems. The fault latch is set in firmware and must be cleared manually through the programming software or HMI — the controller does not poll the cell voltage on boot and self-reset. Navigate to the diagnostic or fault log in your programming environment, acknowledge the battery alarm, and confirm clearance. If the alarm returns within 24 hours, check that the cell is seated correctly and contact voltage at the battery terminal reads at or above 3.5V.