About this replacement
Legrand 61799 / G5 Series — 8.4V Ni-CD Replacement Battery (805806)
This is an 8.4V, 2000mAh nickel-cadmium battery for Legrand emergency lighting units, including the 61799, 061799, and G5 series fittings. It replaces OEM part numbers 805806 and H95473. The cell restores backup illumination capability when the original battery can no longer sustain the fitting through a full duration test.
- 61799, 061799 and G5 fitting compatibility: These fittings share the same 8.4V charge rail, cell geometry at 294.70 × 23.00 × 23.00mm, and trickle-charge controller. The BMS handshake on each accepts Ni-CD cells within the standard float voltage window, so no firmware changes are needed.
- Bench tested on actual hardware: We cycled this cell through a simulated mains-failure event, confirmed the fitting switched to battery within the required time, and verified the charge controller returned to green float status after a full recharge cycle.
- First test-cycle conditioning: Run the manual test button for the full rated duration within 24 hours of installation. This allows the charge controller to register the new cell capacity and ensures the fitting records a valid result before your next scheduled compliance inspection.
Charge indicator staying red after new battery installation
Ni-CD cells can sit in storage for months before reaching the end user, which drops their resting voltage below the charge controller's float acceptance window. When the controller sees a voltage outside that range, it holds the fault or charging state rather than switching to green. Leave the fitting connected to mains for a full 24-hour charge cycle before expecting the indicator to change. If the LED is still red after 24 hours, check terminal contact and confirm cell voltage at the connector reads above 7.2V.
Emergency light dims and cuts short during a duration test
A new cell that has not yet completed one full charge-discharge cycle will not deliver its rated 2000mAh on first draw. The fitting dims or shuts off early because the cell voltage sags under load before the full test period ends. This is not a faulty cell — it is an uncharged one. Charge for a minimum of 24 hours, then run the full manual test; the cell should hold voltage across the entire duration at that point.