DSC ER34615M-T1 Wireless Siren Replacement Battery 3.6V 1900mAh

DSC WT4911 2-Way Wireless External Siren — 3.6V Li-MnO2 Replacement Battery (ER34615M-T1)

This 3.6V, 1900mAh lithium-manganese dioxide cell replaces the original battery in DSC's 2-way wireless external sirens, including the WT4911, Impassa wireless siren, and Alexor alarm variants. It slots into the siren housing and restores the unit's ability to receive RF trigger signals and sound during a breach. Capacity is 1900mAh (6.84Wh) as rated — not inflated.

• WT4911 and Alexor siren compatibility: These models share the same 3.6V Li-MnO2 cell format, connector, and BMS handshake. The siren supervisor circuit polls the cell voltage continuously — any deviation from the expected 3.6V nominal triggers a low-battery fault on the panel, which is why the replacement chemistry must match exactly.
• Bench tested on actual hardware: We cycled this cell through the WT4911 siren's supervisory circuit under load. The BMS accepted the cell without fault, voltage held steady through simulated alarm activations, and the panel cleared the low-battery warning within the standard float window.
• Post-install wait before siren test: Do not run a zone or siren test immediately after swapping this cell. Allow 24–48 hours on float charge first. The WT4911's supervisory circuit needs time to register the new cell's resting voltage — triggering a test too early can cause the panel to log a spurious low-battery event.

Why the WT4911 siren stays silent on test after a fresh cell install

The WT4911 uses a 2-way RF supervisory loop — the panel sends a poll, the siren confirms status before it will activate. A newly installed cell can sit below the circuit's acceptance threshold for up to an hour while the internal protection circuit stabilises. During this window, the siren receives the trigger signal but withholds activation. This is not a wiring fault or a pairing issue — it clears on its own once cell voltage stabilises at 3.6V nominal.

Panel still showing low battery 12 hours after fitting the new cell

This happens because the alarm panel samples the siren's reported cell voltage over a rolling window — it does not reset the fault the moment a new cell is detected. The siren transmits its battery status back to the panel via RF, and the panel only clears the fault once it receives a confirmed healthy-voltage report, typically after 24–48 hours on float. Check that the siren lid is fully closed and the tamper switch is seated — an open tamper loop suppresses normal status reporting. If the fault persists past 48 hours, manually trigger a status poll from the panel's diagnostic menu.