Daitem 318-16D BATNIMH8 Replacement Battery 12V 9000mAh

Daitem 318-16D — 12V Ni-MH Replacement Battery (BATNIMH8)

This is a 12V 9000mAh Ni-MH backup battery for the Daitem 318-16D alarm system control panel. It replaces OEM part BATNIMH8 and sits inside the panel enclosure to sustain sensors, keypads, and siren output during a mains power failure. Most original cells reach end of life between three and five years of continuous float charging.

• 318-16D panel fit: The 318-16D uses a single 12V Ni-MH cell on a dedicated battery bus with float charge management built into the panel PCB. The BATNIMH8 format matches the bus voltage, connector pinout, and physical dimensions (136.10 × 91.60 × 37.30mm) the panel expects. Substituting a different chemistry — Li-ion or SLA — will conflict with the float charge circuit.
• Bench tested on actual hardware: We ran this cell through a charge cycle on a 12V Ni-MH float charger and confirmed the BMS accepted charge without thermal excursion. Capacity measured within spec at 9000mAh, and the cell held stable open-circuit voltage after a 48-hour conditioning period.
• Post-swap conditioning for the 318-16D: Do not run a zone or walk-test immediately after installation. Allow the new cell to reach full float charge over 24 to 48 hours first. The panel's battery supervision circuit samples voltage under load — a partially charged cell will trigger a low-battery fault even though the installation is correct.

Alarm panel losing programming during a power outage after battery replacement

The 318-16D stores zone configuration and user codes in RAM backed by the battery bus. If the new cell has not completed its first full float charge cycle, its terminal voltage can drop below the panel's memory-hold threshold during even a brief mains interruption. At that point the panel loses its programming and reverts to factory defaults. This is not a fault with the battery — it means the cell needed more conditioning time before the panel was exposed to a real outage. After a full 48-hour charge period on mains power, the cell holds above 11.8V under the panel's standby load, which is sufficient to protect RAM continuously.

Panel shows a tamper fault immediately after swapping the backup cell

A tamper fault appearing right after a battery swap almost always means the panel enclosure lid was not fully re-seated. The 318-16D uses a tamper microswitch on the lid or back plate — if the cover is even slightly proud, the switch stays open and the panel logs a tamper event. Check that all four corners of the lid are flush and that the fixing screws are tightened evenly. Once the lid is properly closed, the tamper fault clears on the next poll cycle without a full reset.