Big Beam N71F Emergency Light Replacement Battery 7.2V 800mAh

BIG BEAM ECHL1RWW / ECHL2RWW Series — 7.2V Ni-CD Replacement Battery (N71F)

This is a 7.2V, 800mAh nickel-cadmium replacement battery for BIG BEAM emergency lighting units. It fits the ECHL1RWW, ECHL2RWW, ERXL1WGCS, ERXL1WRCR, and compatible models in the same family. The OEM part number is N71F, also cross-referenced as 3YAJ7, 118-0017, and OSA026.

• Multi-model compatibility: These BIG BEAM fixtures share the same 7.2V battery rail, connector pinout, and charge controller logic across the ECHL and ERXL sub-families. A single cell type works across all of them because the trickle charge circuit is calibrated to the same float voltage and capacity class.
• Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on the BIG BEAM charge circuit. The BMS accepted the cell without fault, held float charge correctly, and the load test confirmed the cell delivers current at the rated 800mAh capacity.
• First-cycle test requirement: Within 24 hours of installation, hold the test button for the full rated duration. This lets the charge controller register the new cell's capacity and clears any residual fault state before your next scheduled compliance inspection.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-CD cell is rarely at full capacity out of the box. Storage discharge means the cell may hold only a fraction of its 800mAh rating on first activation. The BIG BEAM charge controller needs one complete charge cycle — typically 24 hours on mains — before the cell reaches rated capacity. Run the duration test only after that first full charge, not immediately after fitting the new battery.

Charge indicator staying red after new battery installation

The charge indicator stays red when the controller detects cell voltage outside its float acceptance window. A battery shipped at low storage voltage will read below the expected threshold, triggering a fault state. Give the unit a full 24-hour charge on mains power — the controller will re-enter float mode and shift the indicator to green once voltage climbs into range. If the light stays red beyond 30 hours, check the cell seating and connector contact before assuming a controller fault.