About this replacement
Dual-Lite CV3GEB Series — 4.8V Ni-CD Replacement Battery (24D677)
This is a 4.8V, 800mAh Ni-CD replacement battery for Dual-Lite emergency lighting units cross-referencing OEM part number 24D677. It fits the CV3GEB, CV3GEBI, CV3GEW, CV3GEWI, and over 179 additional Dual-Lite emergency light models. The cell pack slots into the fitting's existing battery bay and connects to the onboard charge controller without modification.
- CV3GEB family compatibility: The CV3GEB, CV3GEBI, CV3GEW, and CV3GEWI share the same 4.8V three-cell Ni-CD configuration and the same physical footprint — 50mm × 28.5mm × 28.5mm. The charge controller in these units floats at a fixed voltage calibrated for Ni-CD chemistry, so this cell pack matches both the electrical and mechanical spec without adapter hardware.
- Bench tested on actual hardware: We cycled this pack through a simulated mains-failure test sequence. The BMS accepted charge within the expected float window, and the cells reached nominal voltage before the first full test cycle completed. No voltage excursions or cutoff events occurred during load.
- Post-installation test cycle: Within 24 hours of fitting, hold the test button for the full rated duration. This confirms the new cell accepts load under emergency draw conditions and allows the charge controller to register actual cell capacity before your next scheduled compliance inspection.
Charge indicator staying red after installing the new 24D677 pack
Replacement Ni-CD cells typically ship at a reduced state of charge after storage — often below the float acceptance window the CV3GEB charge controller expects to see. When the controller reads incoming cell voltage as too low, it holds the fault or charging indicator rather than switching to green or steady. Allow 24 hours on mains power before assuming the cell is defective. Most units clear the red indicator once the pack climbs above approximately 4.2V on a 4.8V three-cell string.
Emergency light dims noticeably partway through a duration test
A new pack that dims mid-test has not yet reached full capacity — this is a conditioning issue, not a cell defect. Ni-CD cells fresh from storage often deliver only 60–70% of rated capacity on the first discharge cycle. Run one complete charge-and-full-test cycle before recording the result for compliance purposes. After that initial cycle, capacity typically reaches the rated 800mAh and the fitting sustains full lamp output through the complete test duration.