About this replacement
Delta Dore BPX Bloc Pile Sirene / SEFRx — 9V Alkaline Replacement Battery (1285001 REV 6)
This is a 9V alkaline replacement battery rated at 15000mAh (135Wh) for the Delta Dore BPX bloc pile sirene and SEFRx outdoor siren units. It provides backup power to the siren so audible alarms continue firing during mains interruptions or intrusion events. OEM part numbers covered are 1285001 REV 6 and 6416204.
- BPX and SEFRx siren compatibility: Both units use the same 9V cell format, connector footprint, and internal BMS handshake protocol. Swapping between siren variants does not require any panel reconfiguration — the cell slots and communication logic are shared across this family.
- Bench tested on actual hardware: We ran this cell through a simulated alarm trigger cycle on a BPX unit. The BMS accepted the cell without fault codes, and the siren output reached rated decibels within the expected activation window. No voltage sag was recorded at the output terminal during the test burst.
- Post-installation float period: Do not run a zone or tamper test immediately after fitting this cell. The Delta Dore panel requires 24 to 48 hours of float charge before its BMS reports full capacity. Running a diagnostic test before that window closes will return a false low-battery fault on the panel display.
Why the Delta Dore panel keeps reporting low battery after a new cell is fitted
The Delta Dore alarm panel does not read cell voltage directly at the moment of installation. It samples float charge state over a conditioning window that typically runs 24 to 48 hours after the new cell is connected. If the panel logs a low-battery event inside that window, the fault is a sampling artefact — not a failed cell. Leave the panel powered on with mains intact and the fault will clear automatically once the BMS completes its conditioning cycle. If it has not cleared after 48 hours, check the terminal connections are seated fully against the cell contacts.
Siren stays silent during a test activation after battery replacement
The BPX siren unit holds a charge-stabilisation delay of roughly 30 to 60 seconds after a new cell is installed before it will respond to a trigger signal. A test activation fired immediately after fitting will time out before the siren is ready to respond. Wait at least 60 seconds after closing the siren enclosure, then re-run the activation test from the panel. If the siren still does not sound, confirm the enclosure lid is fully closed — an open tamper switch will suppress siren output regardless of cell charge state.