Arts 805809 Emergency Light Replacement Battery 2.4V 2000mAh

Arts 805809 — 2.4V Ni-Cd Replacement Battery for Emergency Lighting

This is a 2.4V 2000mAh Ni-Cd replacement cell for emergency lighting fittings using the Arts 805809 battery. It restores backup illumination function to exit lights and emergency fixtures that activate on mains failure. Voltage and capacity match the original specification — 2.4V, 2000mAh (4.8Wh).

• Emergency lighting application: Emergency lighting fittings run a trickle charge circuit sized for Ni-Cd chemistry. This cell matches the float voltage window the charge controller expects. Swapping to a different chemistry without reconfiguring the charge circuit causes overcharge damage or a permanent fault LED.
• Bench tested on actual hardware: We cycled this cell through a full mains-failure simulation. The BMS accepted the load at activation, held stable output through the discharge curve, and returned to float charge without triggering a fault state on the controller.
• First-install test cycle: Perform a manual test within 24 hours of fitting by holding the test button for the full rated duration. This lets the charge controller register the new cell and confirms it accepts load before your next scheduled compliance inspection.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-Cd cell rarely arrives at full capacity — storage and transit drain it below the float charge threshold. The fitting's charge circuit typically delivers a low trickle current, so reaching rated capacity can take 24 hours or more after installation. Running a duration test too soon means the cell cannot sustain output for the full rated period, triggering a fail result. Allow a full charge cycle before submitting the fitting to any compliance duration test.

Charge indicator staying red after new battery installation

Some emergency lighting controllers will not exit fault mode automatically once a replacement cell is fitted. If the cell voltage on arrival sits outside the controller's float acceptance window — common after extended storage — the controller flags it as a fault rather than beginning a charge cycle. On most fittings, a manual reset is required: disconnect mains power briefly, reconnect, and allow the controller to re-initialise with the new cell present. After reset, voltage should climb toward 2.8V within the first hour of trickle charge.