About this replacement
Dual-Lite EV2 / CV3REB Series — 2.4V Ni-MH Replacement Battery (784H66)
This is a 2.4V, 1500mAh Ni-MH cell that replaces the original backup battery in the Dual-Lite EV2 and CV3REB series emergency lighting units. These fittings provide illumination during mains failure, and this cell is what keeps them running when grid power drops. Without a functional cell, the fitting will not meet its rated emergency duration during a compliance test.
- EV2 and CV3REB series compatibility: These models share a common charge controller architecture and the same 2.4V trickle float voltage rail. The physical connector and cell footprint are identical across EV2, CV3REB, CV3REW, and CVD1REBN fittings, which is why a single cell SKU covers all of them.
- Bench tested on actual hardware: We ran this cell through a full charge cycle and a load test simulating mains failure activation. The BMS accepted the cell without fault, and voltage held steady across the rated discharge window without dropping below the cutoff threshold.
- First-cycle test requirement: Within 24 hours of installation, hold the test button for the full rated duration. This confirms the new cell accepts load and lets the charge controller register the cell before your next scheduled compliance inspection.
Charge indicator staying red after new battery installation
Ni-MH cells lose voltage during storage. If the cell voltage sits outside the charge controller's float acceptance window when first installed, the controller treats it as a fault rather than a depleted cell. The red LED stays on because the controller has not yet confirmed a successful charge cycle. Leave the fitting powered on mains for a full 24-hour charge cycle — most Dual-Lite controllers will shift to green once the cell reaches approximately 2.4V at the float rate.
Emergency light dims and drops out partway through a duration test
A new cell that has not completed a full conditioning cycle will not deliver its rated 1500mAh on the first discharge. The cell chemistry needs one complete charge-discharge cycle to reach full capacity. If the light dims or cuts out before the rated duration is complete, recharge for 24 hours and run the test again. If it still fails on the second full cycle, check the cell voltage under load — it should hold above 2.0V during the test.