Simon Xti Alarm Panel 6V Replacement Battery 2500mAh

Simon Xti Alarm Panel — 6V Ni-MH Replacement Battery

This is a 6V 2500mAh Ni-MH backup battery for the Simon Xti security control panel. It sits inside the panel enclosure and keeps the system live during mains power outages. When the original cell degrades, the panel cannot hold zones armed or trigger the siren without it.

• Simon Xti panel fit: The Xti uses a dedicated 6V Ni-MH cell wired directly to the panel's charge circuit. The BMS on the board trickle-charges the cell at float voltage continuously. A cell that no longer accepts charge breaks that loop and leaves the panel unprotected during any outage.
• Bench tested on actual hardware: We connected this cell to the Simon Xti charge circuit and monitored voltage uptake over 48 hours. The BMS accepted the cell, voltage climbed to float within the expected window, and the panel cleared its low-battery fault after the conditioning cycle completed.
• Float charge conditioning after install: Do not run a zone or siren test immediately after fitting this cell. The panel charge circuit needs 24–48 hours to bring the new Ni-MH cell to full float charge. Running a diagnostic test before that window closes will trigger a low-battery report even on a healthy new cell.

Why the Simon Xti still reports low battery hours after a new cell is fitted

The Xti panel does not register a new battery as "full" the moment it is connected. The on-board charge circuit brings the Ni-MH cell up from its shipping state through a controlled trickle charge. Until the cell voltage reaches the panel's float threshold — typically around 6.9–7.0V measured at the terminals — the panel will continue to show a low-battery fault. This is normal behaviour, not a fault with the replacement cell. Allow 24–48 hours on mains power before concluding there is a problem.

Alarm losing programming during a power outage after battery replacement

If the panel loses zone settings or user codes the first time mains power drops after a battery swap, the new cell had not yet reached sufficient charge to sustain the panel's memory. The Xti draws a small but constant current to hold SRAM-backed configuration during outages. A cell below roughly 5.8V under load cannot meet that draw. Fit the battery, leave the panel on mains for a full 48 hours before the next outage or test, and the cell will be conditioned enough to carry the load.