ONELUX NCD24SS 2.4V Ni-MH Replacement Battery 8000mAh

ONELUX NCD24SS — 2.4V Ni-MH Replacement Battery

This is a 2.4V, 8000mAh Ni-MH replacement cell for the ONELUX NCD24SS emergency lighting unit. It fits emergency exit signs, ceiling-mounted emergency lights, and backup lighting fixtures used in commercial and residential buildings. Swap it in when the original cell can no longer hold a charge or fails a timed duration test.

• NCD24SS cell compatibility: The NCD24SS charge controller runs a fixed 2.4V float rail. This cell matches that voltage and the physical footprint — 121.10 x 33.65 x 33.00mm — so the charge circuit operates within its acceptance window without modification.
• Bench tested on actual hardware: We ran this cell through a full charge cycle and a mains-failure simulation. The charge controller accepted the new cell, transitioned from charge to float, and the fitting activated cleanly on simulated mains loss.
• First-cycle test requirement: Within 24 hours of installation, hold the test button for the full rated duration. This confirms the cell accepts load and lets the charge controller register the new capacity before your next scheduled compliance test.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-MH cell is not at full capacity — it ships in a partial state of charge from storage. The charge controller needs one complete charge cycle, typically 24 hours on mains, before the cell reaches rated capacity. Running a duration test too soon will result in the light cutting out before the test period ends, even though the cell itself is not faulty. Allow a full 24-hour charge, then perform the test.

Charge indicator staying red after new battery installation

Some NCD24SS fittings require the replacement cell to enter the float acceptance window before the charge LED shifts from red to green. A cell that has sat in storage may present a resting voltage slightly outside that window, causing the controller to hold in fast-charge mode longer than expected. This is normal behaviour — leave the fitting on mains power for a full charge cycle. If the LED has not shifted to green within 24 hours, check the cell connections and confirm the terminal voltage reads at least 2.4V with a multimeter.