Daitem 330-23 Compatible Battery 3.7V 2600mAh Li-ion

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

This is a 3.7V, 2600mAh Li-ion cell for the Daitem 330-23 and 330-23x wireless alarm systems. It replaces OEM part numbers 951-21X and 500798. The battery powers the wireless transmitter and sensor modules that keep these panels active between mains cycles.

• 330-23 and 330-23x compatibility: Both variants run the same 3.7V single-cell architecture with matching connector pinout and BMS handshake protocol. Swapping between the two variants does not require a different cell — the panel reads state-of-charge from the same register on both.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a 330-23 panel. The BMS accepted the cell without fault, held float charge correctly, and the panel cleared its low-battery flag within the expected window after full charge.
• Post-installation float charge: Do not run a zone test immediately after fitting this cell. The panel BMS needs 24 to 48 hours on float charge before it reports accurate state-of-charge. Running a diagnostic test inside that window will trigger a false low-battery warning, even on a fully functional new cell.

Alarm panel showing low battery hours after installing a new cell

The Daitem 330-23 BMS does not immediately accept a new cell as fully charged — it waits for the cell voltage to stabilise at float before updating its internal register. A fresh cell sitting below 4.1V when fitted will trigger a low-battery event on the panel display even if the cell is not faulty. Leave the panel connected to mains and allow 24 to 48 hours before checking battery status. If the warning persists past 48 hours, measure the cell voltage directly — it should read 4.1V or above at full charge.

Alarm losing panel programming during a power outage after battery replacement

When a replacement cell has not completed its initial conditioning cycle, it cannot sustain the panel's memory voltage during a mains outage. The panel treats the insufficient backup supply as a power failure and resets stored zone data. This is not a cell defect — it is a timing issue with BMS acceptance. Allow 48 hours of continuous mains-connected charging after fitting the new cell before the backup function is fully active.