Daitem 520-27D Alarm Backup Battery 10.5V 5500mAh BATV22

Daitem 520-27D / 562-27D / 568-27D — 10.5V Alkaline Replacement Battery (BATV22)

This is the BATV22 alkaline backup battery for the Daitem 520-27D, 562-27D, and 568-27D alarm panel series. It runs at 10.5V with a 5500mAh (57.75Wh) capacity. The battery maintains the panel's backup power during mains failure, keeping sensors and communication circuits active.

• 520-27D, 562-27D, and 568-27D panel fit: All three models share the same battery bay dimensions, voltage rail, and BATV22 connector footprint. The panel's charge circuit is calibrated to the 10.5V alkaline profile — swapping in a different voltage or chemistry will trigger a fault condition at the BMS.
• Bench tested on actual hardware: We ran the BATV22 on a 520-series panel and confirmed the BMS accepted the cell within the expected float charge window. The panel cleared its low-battery flag after the conditioning period without any manual reset.
• Post-installation charge window: Do not run a zone or siren test immediately after fitting this cell. Allow 24–48 hours on float charge first. The panel's BMS samples battery voltage during diagnostics — if the cell hasn't reached full float charge, the panel will report low battery even with a new cell installed.

Alarm panel losing saved programming during a power outage after battery replacement

The Daitem 520-series panel stores zone config and user codes in non-volatile memory, but the processor still needs a minimum supply voltage to execute the handoff from mains to battery. If the BATV22 hasn't completed its 48-hour conditioning cycle, its resting voltage may sit below the panel's switchover threshold. When mains drops, the panel can't draw enough current from an undercharged cell, causing a cold reset. Fit the new battery, restore mains power, and let the system sit undisturbed for 48 hours before testing any power-fail scenarios.

Siren not sounding on test after fitting a new BATV22

After a fresh battery install, the 520-series panel enforces a charge-stabilisation delay before enabling the siren output on battery-only power. This is built into the panel firmware — it's not a wiring fault or a dead siren. The delay typically runs 30–60 seconds after the test trigger. If the siren still doesn't fire after that window, check that the panel lid is fully closed and latched — an open tamper circuit will suppress the siren output regardless of battery state.