Dual-Lite 16U264 Emergency Light Replacement Battery 8.4V 2500mAh

Dual-Lite PGB / PGP / PGW / PGZ Series — 8.4V Ni-CD Replacement Battery (16U264)

This is an 8.4V 2500mAh Ni-CD replacement battery for Dual-Lite emergency lighting fixtures in the PGB, PGP, PGW, and PGZ series. It replaces OEM part number 16U264 and restores backup illumination capability when the original cell has degraded. Voltage and physical dimensions match the factory cell — 177.80 x 52.40 x 25.70mm.

• PGB / PGP / PGW / PGZ compatibility: These four fixture variants share the same 8.4V battery bay, connector pinout, and charge controller float voltage. One cell fits all four because the charge circuit targets the same voltage threshold across the range — no firmware or hardware differences affect battery acceptance.
• Bench tested on actual hardware: We cycled this cell through a full charge-discharge sequence on a PGB fixture. The charge controller accepted the cell without fault, the BMS responded correctly to float voltage, and the load test confirmed stable output through the full rated duration.
• First-cycle conditioning on emergency fixtures: Hold the test button within 24 hours of installation and run the fixture through one complete load cycle. This lets the charge controller register the new cell capacity before any scheduled compliance test. Skipping this step is the most common reason a freshly installed cell fails a duration check.

Charge indicator staying red after new battery installation

A Ni-CD cell stored in a warehouse typically arrives at a low resting voltage — often below the float acceptance window the PGB charge controller expects. When the controller sees a voltage outside that window, it holds in fault mode and keeps the indicator red instead of switching to green. This is not a faulty cell or a faulty fitting. The controller needs to push enough current through the cell to bring terminal voltage up before it will exit fault state. Leave the fitting on mains power for a full 24-hour charge cycle before drawing any conclusions — terminal voltage should stabilise above 8.0V at that point.

Emergency light dims partway through a duration test

If the fixture dims or cuts out before completing the rated test duration, the cell has not yet reached its full charge capacity — this is a conditioning issue, not a defective cell. Ni-CD cells that have been in storage lose capacity in a way that only corrects after one or two complete charge-discharge cycles on the actual fixture. Run one full manual test cycle, then allow a complete 24-hour recharge before testing again. Capacity typically recovers to rated output by the second cycle, and the fixture should then hold load for the full duration.