About this replacement
Daitem 318-16D — 12V 4500mAh Ni-MH Replacement Battery (BATNIMH4)
This is the backup battery for the Daitem 318-16D alarm system control panel. It sits on continuous float charge and takes over when mains power fails. Rated at 12V and 4500mAh, it matches the OEM BATNIMH4 specification.
- 318-16D panel compatibility: The 318-16D uses a dedicated Ni-MH pack at this exact voltage and connector pinout. The BMS in the panel monitors charge state continuously — a mismatch in cell count or chemistry trips a fault immediately.
- Bench tested on actual hardware: We ran this pack through charge acceptance on a float charger simulating the 318-16D charge circuit. The BMS handshake completed without fault codes, and the pack held voltage under a controlled discharge load.
- Post-installation float period: Do not run a zone or siren test immediately after fitting this battery. The panel needs 24–48 hours on float charge before it registers the cell as fully conditioned. Testing before that window will trigger a low-battery report even on a good pack.
Alarm panel showing low battery hours after installing a new cell
Ni-MH packs ship in a partially discharged state. The 318-16D panel measures battery health against an internal voltage threshold — if the cell hasn't reached full float charge, the panel flags it as low regardless of whether the pack is new. This is a charge-state issue, not a faulty battery. Leave the panel powered from mains for 48 hours before drawing any conclusions about the replacement cell.
Alarm losing its programming during a mains outage after battery swap
If the replacement pack hasn't completed its conditioning cycle, it may not deliver enough sustained voltage to hold panel memory under load. The 318-16D requires the backup battery to sit above approximately 11V to maintain RAM and zone configuration. A pack that hasn't been on float charge for at least 48 hours may sag below that threshold the moment mains drops. Let the panel charge the new battery for a full two days before testing it on a simulated outage.