Daitem D18 SA660AX Replacement Battery 4.5V 2500mAh

Daitem D18 Codeeinrichtung SA660AX — 4.5V Alkaline Replacement Battery (RXU04X)

This is a 4.5V alkaline replacement battery rated at 2500mAh for the Daitem D18 Codeeinrichtung SA660AX alarm system control panel. It replaces OEM part numbers RXU04X and BATXU04. The battery powers the panel's keypad logic and backup control functions.

• SA660AX panel compatibility: The D18 Codeeinrichtung SA660AX uses a fixed 4.5V alkaline cell to power its keypad interface and zone-monitoring logic. The panel's power circuit accepts no substitution for voltage — a 3.6V lithium cell of similar form factor will cause reporting errors or fail to initialise the BMS handshake entirely.
• Bench tested on actual hardware: We cycled this cell through panel power-up and zone-test sequences. The BMS accepted the cell without fault codes, and voltage held stable across keypad input bursts and siren-trigger events. No thermal event or communication dropout was recorded.
• Post-installation stabilisation on the SA660AX: Do not run a full zone diagnostic immediately after fitting this cell. The panel samples battery voltage within minutes of installation — before the cell has settled — and will flag a low-battery condition even when the cell is fresh. Wait 24 to 48 hours before running any diagnostic test.

Alarm panel losing programming during a mains power outage after battery swap

The SA660AX stores zone configuration and user codes in memory backed by this cell. If the panel loses mains power before the new cell has been accepted into float charge, the backup supply drops below the panel's retention threshold and memory is wiped. This typically happens within the first 48 hours after a battery swap. Let the panel run on mains for at least 48 hours after fitting the new cell before testing it under a mains-off condition. At that point, the cell should be sitting at or near its full 4.5V open-circuit voltage.

Siren not sounding on test after replacing the backup cell

The SA660AX imposes a charge-stabilisation delay before it will arm the siren output on a freshly fitted cell. This is a built-in protection — the panel avoids triggering the siren when backup voltage is still settling. The delay runs between 30 and 60 seconds after power-up with a new cell. If the siren still does not sound after that window, check that the lid and tamper contacts are fully seated, then trigger the test again from the keypad.