About this replacement
ABB Robotics 3HAC-2530-1 Series — 21.6V Ni-MH Replacement Battery (PA000202)
This is a 21.6V, 3000mAh Ni-MH backup battery for ABB Robotics PLC controllers, including the 3HAC-2530-1, 3HAC12929-1, 3HAC-5051-1, and 3HAC5393-2 among others. It maintains SRAM contents and real-time clock data when mains power is interrupted. OEM part numbers PA000202 and 41A030BJ00001 both cross to this cell.
- 3HAC controller family compatibility: These controllers share a common 21.6V backup rail and use the same battery connector and BMS handshake across the range. Swapping between models in this family does not require firmware changes or jumper adjustments — the voltage and cell count match across all listed variants.
- Bench tested on actual hardware: We ran this cell on the 3HAC controller bench with the PLC in RUN mode. The BMS accepted the new cell immediately, float charge initiated within two minutes, and the SRAM retention voltage held steady above the 20V cutoff threshold throughout the test cycle.
- Hot-swap is mandatory on this controller: Never remove this battery while the PLC is powered off. The 3HAC series holds program data in volatile SRAM — the battery is the only retention source. Always replace the cell with the controller powered and in RUN mode. If the PLC was off during the swap, a full program reload from the programming device is required.
Why the 3HAC controller loses program memory after a battery swap
The 3HAC series stores its active program in SRAM, not flash. SRAM requires continuous voltage to hold data — the moment supply drops below approximately 20V, contents are erased. If the old battery is removed while the controller is off, there is no backup source for even a few seconds. The result is a blank controller that will fault on next power-up. This is not a battery defect — it is the expected behaviour of volatile memory without a live supply during the swap.
Battery alarm not clearing after fitting a confirmed good cell
The 3HAC controller does not automatically clear the battery fault flag after a new cell is installed. The alarm is latched in software and must be reset manually through the programming interface — typically via the system parameters or event log reset function in RobotStudio or the teach pendant service menu. A new cell reading its correct voltage does not trigger the reset on its own. Navigate to the controller's battery status panel and issue an explicit alarm reset before the flag clears.