ADT Impassa 7.2V Ni-MH Replacement Battery 3700mAh

ADT Impassa Wireless Alarm Systems — 7.2V Ni-MH Replacement Battery

This 7.2V, 3700mAh Ni-MH cell replaces the backup battery in the ADT Impassa control panel. It keeps the panel live during mains power outages, maintaining zone monitoring, alert transmission, and notification functions. Capacity is sourced from the product data at 3700mAh (26.64Wh).

• Impassa control panel fit: The Impassa panel draws a fixed low-current float charge from a dedicated battery circuit. This cell matches the 7.2V rail, physical footprint (101.40 × 68.30 × 17.20mm), and connector orientation required by that circuit.
• Bench tested on actual hardware: We cycled this cell through charge acceptance and float transition on the Impassa board. The panel's BMS accepted charge without fault codes, and voltage held steady across the float phase without thermal event.
• Post-installation conditioning — Impassa specific: Do not trigger a zone test immediately after fitting this cell. The Impassa panel requires 24–48 hours on float charge before its BMS reports an accurate battery status. Running a diagnostic test before that window closes will produce a false low-battery report on the panel display.

Alarm panel showing low battery hours after installing a new cell

The Impassa BMS does not accept a new cell as "full" at the moment of installation — it needs a full float-charge cycle to recalibrate its state-of-charge reading. If the panel flags low battery within the first day, the cell is not faulty; the BMS simply hasn't completed its conditioning window. Leave the panel on mains power for 48 hours without triggering tests. After that period, the low-battery indicator should clear once voltage stabilises above 7.0V on float.

Alarm losing programming during a power outage after battery swap

If the panel loses zone programming or time settings during a mains outage shortly after a battery replacement, the new cell has not yet been fully accepted by the backup circuit. The Impassa needs approximately 48 hours of continuous mains charging before the backup battery can carry the panel load independently. A cell fitted and then immediately tested by cutting mains power will show this symptom even if the cell itself is good. Restore mains power, allow a full 48-hour conditioning period, then retest by cutting mains — programming should persist.