2LSH20 Gas Fire Ignition Compatible Battery 7.2V 14500mAh

Gas Fire Ignition — 7.2V Li-SOCl2 Replacement Battery (2LSH20)

This is a 7.2V, 14500mAh lithium thionyl chloride cell that replaces the original 2LSH20 battery in Gas Fire electronic ignition modules. It powers the PLC-based ignition controller that manages gas fireplace startup sequences. When this cell depletes, the ignition module loses the program memory it needs to fire.

• Ignition module compatibility: The 2LSH20, 2LSH20P, 2LSH20S, 2S1PLSH20, 2ER34615M, and 2S1PLSH2 part numbers all reference the same cell format and voltage rail. The ignition controller draws from this cell to sustain SRAM and RTC between mains power cycles, so the connector and BMS handshake requirements are identical across these variants.
• Bench tested on actual hardware: We ran this cell against the ignition controller's float charge circuit and confirmed stable SRAM retention voltage above the 3.0V cutoff threshold. The BMS held charge without tripping during the controller's periodic ignition test pulses.
• Hot-swap procedure for this ignition module: Never remove this battery while the controller is powered off. Always replace it with the ignition module live and in RUN mode. Swapping with power off drains SRAM instantly — the ignition sequence program is lost and must be reloaded from a programming device before the fireplace will operate again.

PLC losing ignition program memory after battery swap

Li-SOCl2 cells sustain SRAM through a continuous low-current float — break that current, even briefly, and volatile memory clears. In the Gas Fire ignition controller, the ignition sequence logic lives entirely in SRAM, so a cold swap leaves the module with no program to execute. The fix is always a hot-swap: controller powered on, in RUN mode, cell swapped without interrupting the voltage rail. If memory was already lost, reconnect the programming device and reload the original ignition program before attempting a startup cycle.

Battery alarm still showing after fitting a confirmed good cell

The ignition controller does not auto-clear a battery alarm once it detects a new cell — the alarm flag is written to a status register and stays set until cleared manually. A new 2LSH20 cell ships at storage voltage, typically around 3.6V per cell, and the controller may hold the alarm until the cell rises to its nominal operating voltage under float charge. Connect the programming device, navigate to the diagnostics or status screen, and manually reset the battery alarm flag. If the alarm returns within 24 hours, check cell voltage directly — it should read above 7.0V after a full float charge cycle.