Lithonia ELB2P401N Emergency Light Replacement Battery 2.4V 2100mAh

Lithonia ELB2P401N Series — 2.4V Ni-MH Replacement Battery (ELB 2P401N)

This is a 2.4V, 2100mAh Ni-MH battery pack for Lithonia emergency lighting fixtures. It fits the ELB2P401N, ELB0310, NIC1158, and LV S W 1 R 120/277 EL N, among others. These units back up exit signs and emergency lights when mains power fails.

• Cross-model fit — ELB2P401N platform: All listed models share the same 2.4V charge rail, physical cell footprint, and two-wire connector. The charge controller in each fitting expects a Ni-MH cell at this voltage, so the BMS handshake transfers without modification.
• Bench tested on actual hardware: We ran this cell through a full charge cycle and simulated a mains-fail event. The BMS accepted the cell, pulled charge current normally, and the load circuit activated cleanly on test trigger.
• First-cycle conditioning after installation: Within 24 hours of fitting, hold the test button for the full rated test duration. This lets the charge controller register the new cell's capacity and confirms the cell accepts load before your next scheduled compliance test.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-MH cell ships at a partial state of charge — typically 30–50% of rated capacity. The fitting's charge controller needs at least one full charge-discharge cycle before the cell reaches its rated 2100mAh. Running a duration test too soon means the cell runs out before the test period ends, which reads as a fail even though the cell is not faulty. Allow 24 hours on charge after installation, then run the full test. The cell should hold load at 2.4V throughout.

Charge indicator staying red after new battery installation

Some Lithonia fittings lock the fault LED state in firmware and do not auto-clear it when a new cell is detected. The charge controller measures incoming cell voltage against its float acceptance window — a cell sitting in storage at low voltage can fall outside that window on first connection. If the red LED persists beyond two hours, disconnect the battery, wait 30 seconds, and reconnect to force the controller to re-sample cell voltage. If the LED clears and moves to amber or green within the next charge cycle, the cell is charging normally.