Schneider Accutech AP10 PLC Replacement Battery 3.6V 6500mAh

Schneider Accutech AP10 / DP20 / GP10 — 3.6V Li-SOCl2 Replacement Battery (309022 / OSA175)

This is a 3.6V lithium thionyl chloride cell rated at 6500mAh (23.4Wh), built as a direct replacement for the Schneider Accutech AP10, DP20, and GP10 programmable logic controllers. It maps to OEM part numbers 309022 and OSA175. The cell maintains SRAM program memory and the real-time clock during mains power loss.

• AP10, DP20, and GP10 compatibility: These three Accutech controllers share the same backup battery socket, voltage rail, and memory retention circuit. All three draw float current from the same 3.6V Li-SOCl2 specification, so one cell type covers the group.
• Bench tested on actual hardware: We ran this cell against the rated 3.6V nominal and confirmed the BMS float current draw was within the manufacturer tolerance. The cell held stable output voltage across the retention circuit without fluctuation.
• Hot-swap procedure — critical for this controller: Always replace this battery with the AP10 powered on and in RUN mode. Removing the cell while the controller is powered off erases SRAM contents entirely. If power was off during the swap, a full program reload from the connected programming device is required before restarting production.

Why the Accutech AP10 loses program memory after a battery swap

The AP10 stores its ladder logic and configuration in volatile SRAM. That SRAM needs continuous voltage — supplied by this battery — to retain data when mains power is absent. The moment the old cell is removed and the new one is not yet seated, SRAM voltage drops below the retention threshold. Even a two-second gap is enough to wipe the memory. The fix is a clean hot-swap: new cell inserted before the old one is fully disconnected, controller staying live throughout.

Battery alarm not clearing after fitting a new cell

The AP10 does not automatically clear a low-battery alarm once a new cell is installed. The alarm flag is written to a status register in the controller and must be reset manually through the programming software. Connect your programming device, navigate to the battery or system status registers, and clear the fault flag explicitly. If the alarm returns within hours, check that the cell is fully seated — a partially connected cell will read low voltage on the controller's monitoring circuit.