Dual-Lite EV4D-02L Emergency Light Replacement Battery 2.4V 2000mAh

Dual-Lite EV4D-02L / EV4DI-02L — 2.4V Ni-MH Replacement Battery (784H67)

This is a 2.4V, 2000mAh Ni-MH cell replacement for the Dual-Lite EV4D-02L and EV4DI-02L emergency lighting units. It sits inside the fitting and powers the lamp circuit during a mains failure, keeping evacuation routes lit until primary power returns. Capacity and voltage match the original OEM specification (784H67 / 93035262E).

• EV4D-02L and EV4DI-02L fitment: Both models share the same battery bay dimensions, connector polarity, and 2.4V charge rail. The charge controller in each unit expects a Ni-MH cell at this voltage — swapping to a different chemistry will cause the controller to overcharge or fail to float correctly.
• Bench tested on actual hardware: We cycled this cell through a full charge-then-discharge sequence on the EV4D platform. The charge controller accepted the cell, transitioned from bulk to float charge without fault, and the BMS did not trip during simulated mains-fail load activation.
• First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. A fresh cell from storage may not have reached its full charge state — this first cycle lets the charge controller register actual cell capacity before your next scheduled compliance inspection.

Charge indicator staying red after new battery installation

A Ni-MH cell shipped from a warehouse typically sits at a partial state of charge — often below the float acceptance window the EV4D charge controller expects to see. When the controller measures cell voltage on first connection, it may flag a fault instead of entering normal charge mode. Leave the fitting connected to mains for a full 24-hour period without triggering the test button. Most controllers will clear the red indicator once the cell climbs past approximately 2.2V resting voltage and the charge circuit detects normal acceptance current.

Emergency light dims or cuts out partway through a duration test

This is not a faulty cell — it is a cell that has not completed its first full conditioning charge. A Ni-MH cell that has been in storage for several months will not deliver rated capacity on its first discharge. The charge controller needs at least one uninterrupted 24-hour charge cycle before the cell reaches its 2000mAh rating. If the light dims during a compliance test shortly after installation, allow a full charge cycle, then re-run the duration test from a confirmed full-charge state.