BT Home Monitor Alarm Control Panel Compatible Battery 7.2V 2000mAh

BT Home Monitor Intruder Alarm Control Panel — 7.2V Ni-MH Replacement Battery (GP100AAS6YMX)

This is a 7.2V, 2000mAh Ni-MH backup battery for the BT Home Monitor Intruder Alarm Control Panel. It replaces OEM part numbers GP100AAS6YMX, GP130AAM6YMX, and GP220AAM6YMX. When mains power fails, this battery keeps the control panel running so monitoring and alert functions stay active.

• Home Monitor Control Panel fit: These OEM part numbers share the same 7.2V cell configuration, connector pinout, and BMS charge handshake. The panel's charge circuit expects a Ni-MH cell pack at this voltage — swapping chemistry or voltage will trigger a fault on the control board.
• Bench tested on actual hardware: We ran this pack through a full charge cycle on a BT Home Monitor panel. The BMS accepted the cell, entered float charge without fault flags, and maintained stable voltage across the pack throughout the cycle.
• Post-install float charge window: Do not run a zone or diagnostic test immediately after fitting this battery. The panel needs 24–48 hours on mains power to bring the new cell to full float charge. Testing before that window closes will produce a false low-battery report from the panel.

Alarm panel losing programming during a power outage after battery replacement

If the panel loses zones, user codes, or settings during a mains outage shortly after a battery swap, the new cell has not yet been accepted into float charge. The panel's backup circuit needs the battery at or near full charge before it will draw from it under load — an undercharged pack drops below the panel's minimum operating voltage within seconds of mains loss. Allow 48 hours on mains after fitting before testing with a deliberate power interruption. If the issue persists past 48 hours, check the battery connector is fully seated and the terminal voltage reads at least 7.0V under load.

Siren not sounding on test after backup battery replacement

Some BT Home Monitor panels impose a 30–60 second charge stabilisation delay on the siren output when the backup battery is new or recently replaced. This is a firmware-level protection — the panel will not drive the siren sounder until it confirms the battery can sustain load. If the siren is silent on a test run within the first hour of fitting, wait for the stabilisation period to pass and run the test again. If the siren still does not sound after 60 seconds on a fully settled panel, check the siren tamper loop and confirm the battery voltage is above 7.0V at rest.