LFI BL93NC487 Emergency Light Replacement Battery 4.8V 1500mAh

LFI BL93NC487 — 4.8V Ni-MH Replacement Battery

This is a 4.8V, 1500mAh Ni-MH replacement battery for emergency lighting fixtures that use the LFI BL93NC487 cell pack. It fits commercial and residential emergency lights and exit signs that run on a 4.8V Ni-MH configuration. When the original cell degrades and the fitting fails its duration test, this unit restores the backup illumination capacity.

• Emergency lighting cell pack: Emergency lighting fixtures on a 4.8V Ni-MH platform share a consistent float charge voltage and connector footprint. The BL93NC487 form factor — 50.00 x 28.40 x 28.40mm — fits directly into the cell bay without modification. The charge controller continues its normal float cycle without requiring reconfiguration.
• Bench tested on actual hardware: We ran this cell through a full charge cycle and applied a sustained load matching emergency lighting draw. The cell accepted charge cleanly, voltage held stable under load, and there was no BMS dropout during the discharge phase.
• First-cycle test within 24 hours of installation: Hold the test button for the full rated duration within 24 hours of fitting the new cell. This lets the charge controller register the new cell capacity and confirms the cell accepts load before your next scheduled compliance test. A new Ni-MH cell pulled from storage may not be at full charge state on arrival.

Charge indicator staying red after new battery installation

Emergency lighting charge controllers use a float voltage window to determine when a cell is fully charged and switch the LED from red to green. A Ni-MH cell that has been in storage can sit below that acceptance window, so the controller sees a voltage deficit and holds red. The cell is not faulty — it needs a full charge cycle to bring terminal voltage up into the float acceptance range. Leave the fitting powered for 24 hours after installation. If the indicator has not moved to green after that period, check the mains supply to the fitting and confirm the charge circuit is active — float voltage at the cell terminals should read between 5.5V and 5.8V for a healthy 4.8V Ni-MH pack.

Emergency light dims and cuts short during a duration test

This is not a faulty cell — it is a conditioning issue on first activation. A Ni-MH cell that has not completed a full charge-discharge cycle after installation will not deliver its rated capacity immediately. The charge controller has not yet mapped the new cell's capacity curve, so it cannot sustain full output for the test duration. Run one complete manual test cycle — full charge, then hold the test button through the full rated period — before any compliance inspection. After that first full cycle, the cell delivers its rated 1500mAh and the fitting should pass the duration test at the correct output level.