About this replacement
Paradox Magellan MG6250 — 4.8V Ni-MH Replacement Battery (PDX-BATMG6250)
This is a 4.8V, 1500mAh Ni-MH backup battery for the Paradox Magellan MG6250 alarm control panel. It fits the MG6250 console directly, using the same connector and cell configuration as the original. When mains power drops, this battery keeps the panel active, maintaining zone monitoring and programmed settings.
- MG6250 panel compatibility: The MG6250 and MG6250 Control Panel share the same battery bay, connector pinout, and 4.8V charging rail. The panel's onboard charger float-charges the Ni-MH pack at a fixed rate — no programming changes needed after swapping the cell.
- Bench tested on actual hardware: We ran this pack through the MG6250 charge cycle and confirmed the BMS accepted the cell without fault codes. Float charge voltage stabilised within expected range, and the panel cleared its low-battery flag after the conditioning period.
- Post-installation charge window: Do not run a zone or siren test immediately after fitting this battery. The MG6250 needs 24 to 48 hours on float charge before the panel accurately reads battery state. Running a diagnostic test before that window closes will often trigger a false low-battery report.
Alarm panel losing programming during a power outage after battery replacement
If the MG6250 loses its zone and user settings during a mains outage, the backup battery has not yet been accepted into the panel's charge circuit. A freshly installed Ni-MH cell starts at a partial state of charge and cannot sustain panel logic until it completes at least one full float cycle — typically 48 hours. During that window, a brief outage can pull the cell voltage low enough for the panel to reset. Let the panel sit on mains power for 48 hours before treating the battery as ready for backup duty.
MG6250 showing low battery fault hours after fitting a new cell
A low-battery flag appearing within the first day of installation is almost always a charge-state reporting issue, not a faulty cell. The MG6250 polls battery voltage at regular intervals, and a new Ni-MH pack sitting below 5.2V will trip the fault threshold even if the cell is undamaged. This clears on its own once float charge raises the pack voltage above the panel's acceptance level. If the fault persists beyond 48 hours of uninterrupted mains power, check that the battery connector is fully seated — a partial connection causes the same symptom.