Legrand 131607 Emergency Light Compatible Battery 3.6V 4000mAh

Legrand 131607 Series — 3.6V Ni-CD Replacement Battery (MXN0050)

This is a 3.6V, 4000mAh nickel-cadmium cell for Legrand emergency lighting fittings. It fits the 131607, 137973, 186003, and 615910 models, plus 11 additional Legrand units in the same series. The cell slots into the fitting's charge circuit and powers the lamp during mains failure.

• Cross-model fit — 131607 series fittings: These fittings share a common 3.6V charge rail and the same physical cell format. The connector pinout and trickle-charge voltage are identical across the range, so one cell covers the full group without modification.
• Bench tested on actual hardware: We cycled this cell through a full mains-failure simulation. The charge controller accepted the cell within the expected float window, and the lamp activated cleanly on the simulated power cut. The BMS registered no fault codes after the first full charge cycle.
• Post-install test cycle: Within 24 hours of fitting this cell, hold the test button for the full rated duration. This lets the charge controller register the new cell's capacity before the fitting logs its next scheduled compliance test. Skip this step and the controller may record a failed duration result against a cell that is actually fine.

Charge indicator staying red after new cell installation

A freshly shipped Ni-CD cell often sits at a lower resting voltage than the fitting's float acceptance window requires. When the controller reads that low open-circuit voltage, it flags the cell as faulty rather than simply discharged. Allow the fitting 12 to 24 hours on mains power before judging the charge state. If the indicator remains red past 24 hours, check that the cell connector is fully seated — a half-engaged pin prevents the charge circuit from closing.

Emergency light dims noticeably during a duration test

A cell that has not completed one full conditioning cycle will not deliver rated capacity under load. The voltage sags early, and the lamp dims before the test period ends. This is not a faulty cell — it is an uncharged one. Run the fitting on mains for a full 24-hour charge, then repeat the test. A conditioned cell should hold the lamp at full brightness to the end of the rated period at 3.6V under nominal discharge load.