About this replacement
Jablotron OS-360A / OS-365A — 4.8V Ni-MH Replacement Battery (N1800SC4BC)
This is a 4.8V 3000mAh Ni-MH replacement battery for the Jablotron OS-360A and OS-365A wireless keypads. These keypads arm and disarm Jablotron intruder alarm systems and rely on this internal cell to maintain operation during mains interruptions. Capacity is 3000mAh (14.4Wh), matching the original specification.
- OS-360A and OS-365A compatibility: Both keypads share the same internal battery bay, connector pinout, and 4.8V charging rail. The panel BMS on each model accepts the same charge profile, so one cell covers both units without any wiring modification.
- Bench tested on actual hardware: We ran this cell through a charge cycle on the OS-360A platform and monitored BMS acceptance. The cell reached float charge within the expected window and the panel cleared its low-battery flag without manual intervention.
- Post-installation charge window: Do not run a zone or diagnostic test immediately after fitting this cell. The panel requires 24–48 hours on float charge before the BMS reports a full battery. Running a test before that window closes will trigger a low-battery fault even on a good cell.
Why the OS-360A reports low battery hours after a new cell is fitted
The OS-360A does not read raw cell voltage to determine battery status. It monitors a charge-acceptance threshold inside the BMS, and a freshly installed Ni-MH cell sits below that threshold until the panel has trickle-charged it for 24–48 hours. This is normal behaviour, not a fault with the replacement cell. The low-battery flag clears automatically once the float charge cycle completes. No reset is required — leave the panel powered and connected to mains for the full conditioning window.
Panel losing stored programming during a power outage after battery swap
If the alarm panel loses its zone configuration or user codes during a mains outage shortly after a battery replacement, the new cell had not yet been accepted by the panel's backup circuit. A Ni-MH cell at partial charge cannot sustain the panel's RAM retention voltage under load. The fix is straightforward: restore mains power, allow 48 hours of uninterrupted charging, then confirm backup voltage has reached at least 4.6V before testing with a deliberate mains disconnection.