Unitech AA500MAH Emergency Light Replacement Battery 4.8V 1500mAh

Unitech AA500MAH — 4.8V Ni-MH Replacement Battery for Emergency Lighting

This is a 4.8V, 1500mAh Ni-MH replacement battery for Unitech emergency lighting units. It fits fittings that reference part numbers AA500MAH, D-AA500mAh, CFS47NC, or 80048800. Swap it in to restore the backup illumination function when the original cell has degraded or failed to hold charge.

• Emergency lighting pack compatibility: These part numbers share the same 4-cell Ni-MH pack configuration, 4.8V nominal rail, and flat-tab connector layout. A fitting wired for one will accept any of these references without modification to the harness or charge controller.
• Bench tested on actual hardware: We ran this pack through a full trickle-charge cycle and a simulated mains-failure discharge. The BMS held stable voltage across the full discharge curve and the charge controller moved from red to green within the expected window.
• First-cycle test requirement: Hold the test button for the full rated duration within 24 hours of installation. This lets the charge controller register the new cell capacity and confirms the pack accepts load before your next scheduled compliance inspection.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-MH cell rarely ships at full capacity. Storage discharge, transport temperature, and shelf time all reduce the initial state of charge before the pack ever sees the fitting's trickle charger. On the first test cycle, the cell may not sustain output for the full rated period even though the battery itself is not faulty. Allow 24 hours on charge before performing any compliance test. One complete charge-discharge cycle is enough for the cell to reach its rated 1500mAh capacity.

Charge indicator staying red after new battery is installed

The charge controller in most emergency fittings uses a voltage threshold to decide whether to enter float charge and flip the LED green. A cell that has sat in storage for months may present a resting voltage just outside that acceptance window, keeping the indicator red even after correct installation. Leave the fitting powered on mains for a full 24 hours — the controller will detect the rising cell voltage once charging begins and switch state. If the indicator is still red after 24 hours, measure the pack voltage directly; it should read between 5.4V and 5.8V on a fully charged 4.8V Ni-MH pack.