Daitem 330-23 Replacement Battery 3.7V 3350mAh 951-21X

Daitem 330-23 / 330-23x — 3.7V Li-ion Replacement Battery (951-21X)

This is a 3.7V 3350mAh (12.4Wh) lithium-ion cell for the Daitem 330-23 and 330-23x wireless alarm control panels. It replaces part numbers 951-21X and 500798. When the original cell degrades, the panel loses its backup power reserve and begins triggering low-battery alerts.

• 330-23 and 330-23x platform fit: Both variants share the same cell bay, connector pinout, and BMS handshake protocol. The 67 × 20 × 18.6mm form factor seats flush with no modification required.
• Bench tested on actual hardware: We cycled this cell through the 330-23 charge circuit and confirmed the BMS accepted the cell, cleared the low-battery flag, and held a stable float voltage. No false tamper codes fired during our test sequence.
• Post-installation float period: Do not run a zone or siren test immediately after swapping the cell. Allow 24 to 48 hours on mains power so the panel can bring the cell to full float charge. Running diagnostics before that window closes can trigger a false low-battery report.

Alarm panel showing low battery hours after installing a new cell

The 330-23 charge controller monitors cell voltage continuously and compares it against a threshold — typically around 3.5V — before clearing the low-battery flag. A fresh Li-ion cell ships at a storage charge of roughly 3.6–3.7V, which sits just above that threshold. The panel BMS needs a full 24 to 48 hours on mains power to bring the cell to its rated float voltage before the warning clears reliably. If the alert persists beyond 48 hours on mains, check that the charge circuit connector is fully seated.

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

The 330-23 uses the backup cell to hold RAM and configuration data during a mains failure. If the new cell has not completed its conditioning period, its available capacity may be too low to sustain the panel's standby draw through an extended outage. This causes the panel to reset, wiping zone assignments and user codes. Install the new cell, leave the panel on mains power for a full 48 hours before any deliberate outage test, and confirm the cell voltage reads at least 4.1V before cutting mains.