BAES MGN9019 4.8V Emergency Light Compatible Battery 2000mAh

BAES 10050038 Series — 4.8V Ni-CD Replacement Battery (MGN9019)

This is a 4.8V 2000mAh nickel-cadmium cell for BAES emergency lighting units, including models 10050038, 789673, 803790, and 804137N. It powers the fitting during mains failure, keeping exit signs and evacuation routes lit. Voltage and capacity match the original BAES specification exactly.

• Multi-model fit across the BAES range: These fittings share the same 4.8V charge rail, connector pinout, and trickle-charge controller logic, so one cell covers the full listed model group without any wiring modification.
• Bench tested on actual hardware: We ran the cell through a full charge cycle and applied a rated discharge load. The cell held voltage above the BMS cutoff threshold for the full test window and recovered cleanly to float charge without controller fault.
• First-cycle test requirement: Perform a manual test within 24 hours of installation by holding the test button for the full rated duration. This confirms the cell accepts load and lets the charge controller register the new capacity before the next scheduled compliance inspection.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-CD cell ships in a partially discharged state after months in storage. The charge controller in BAES fittings applies a trickle float charge, not a fast conditioning cycle, so the cell may not reach full capacity for 24–48 hours post-installation. Running a duration test immediately after fitting will almost always fall short of the rated period. Allow at least one full 24-hour charge before the first compliance test, then confirm the fitting shows a green charge indicator before triggering the test cycle.

Charge indicator staying red after confirmed good installation

Some BAES fittings latch the fault LED in firmware and will not clear it automatically even after the cell voltage returns to the float acceptance window. If the cell measures between 5.4V and 6.0V at rest after 24 hours on charge, the cell itself is not the problem. Locate the manual reset on the fitting's PCB — typically a recessed push-button or a brief mains interrupt procedure — and trigger it to clear the latched fault. If the LED returns red within an hour of reset, re-check the connector seating and confirm the cell polarity is correct before replacing the fitting.