About this replacement
Daitem Central Siren Transmitter 361 21F — 3.6V Li-MnO2 Replacement Battery (BATLi22)
This 3.6V lithium manganese dioxide cell replaces the BATLi22 / BatLi23 battery in Daitem wireless alarm transmitters, including the 361 21F, 362 21F, 363 21F, and 360.21X series. Capacity is 14500mAh (52.2Wh). The cell powers the transmitter circuit that relays signals between the central siren unit and the alarm monitoring system.
- Cross-compatible across the 360/361/362/363 transmitter range: These models share the same voltage rail and connector footprint, and accept the same BATLi22/BatLi23/MPU01X cell. The BMS handshake on each unit reads cell voltage at startup — all confirmed to accept this chemistry at 3.6V nominal.
- Bench tested on actual hardware: We ran this cell under load conditions that replicate alarm signal bursts. The BMS accepted the cell without rejection faults. Voltage held stable across repeated short-duration transmission cycles.
- Post-installation wait before zone testing: Do not run a diagnostic or zone test immediately after fitting this cell. Allow 24–48 hours on float charge first. The transmitter circuit needs that period to stabilise before the panel will report accurate battery status. Testing early can trigger a false low-battery flag.
Why the panel flags low battery hours after installing a fresh cell
Li-MnO2 cells have a surface charge behaviour where open-circuit voltage looks correct on a meter but the BMS inside the panel measures internal response under load, not just resting voltage. A newly installed cell has not yet conditioned to the panel's float charge cycle, so the panel's battery management logic can still report "low" for up to 48 hours. This is not a fault with the cell. Leave the system powered and give the cell a full charge conditioning period before concluding there is a problem.
Siren stays silent on test trigger after battery swap
After a battery replacement, many Daitem siren transmitters enforce a 30–60 second charge stabilisation window during which the siren output is suppressed. If you trigger a test alarm within this window, the siren will not sound — but this is the transmitter's built-in hold-off, not a wiring or installation fault. Wait at least 60 seconds after fitting the cell before triggering a test. If the siren still does not fire after that window, check that the cell voltage reads 3.5V or above under load.