About this replacement
Bticino 4216 / 4280 — 7.4V Li-Polymer Replacement Battery (4238)
This 7.4V 900mAh Li-Polymer cell replaces the Bticino 4238 backup battery in the 4216 and 4280 alarm system control panels. It keeps the panel live during a mains failure so zones, alerts, and system monitoring stay active. Dimensions are 50.10 × 28.00 × 13.00mm — match these before fitting.
- 4216 and 4280 compatibility: Both panels share the same battery bay, 7.4V supply rail, and 4238 part number. The BMS handshake on each panel expects a Li-Polymer cell at this voltage — substituting a different chemistry trips a fault condition.
- Bench tested on actual hardware: We ran this cell through charge acceptance and float voltage on a controlled load. The BMS accepted the cell without fault codes, and float voltage stabilised at the correct level within the expected window.
- Post-installation float charge: Do not run a zone or siren test immediately after fitting. Allow 24–48 hours on mains power so the panel completes its float charge cycle. Testing before that window closes can cause the panel to flag a low-battery condition even on a healthy new cell.
Alarm panel losing programming during a power outage after a battery swap
The 4216 and 4280 store zone configuration and user codes in volatile memory backed by the battery rail. If the panel loses that rail during a mains outage before the new cell is fully conditioned, it cannot hold the memory buffer long enough. The panel then boots to factory defaults when power returns. A 48-hour conditioning period on mains after fitting the new cell lets the charge controller fully accept the cell before it is called on.
Panel showing low battery fault within hours of fitting a new cell
This is a charge-state reporting issue, not a faulty cell. The panel reads the cell's open-circuit voltage on first boot and logs a low-battery event because the new cell has not yet reached float charge. The fault clears on its own once the panel has been on mains for 24–48 hours and the charge controller brings the cell to its target voltage. If the fault persists beyond 48 hours, check that mains power is stable and the connector is fully seated.