ARSEL AK-58 Emergency Light Replacement Battery 3.6V 4000mAh

ARSEL AK-468-1 Series — 3.6V Ni-CD Replacement Battery (AK-58)

This is a 3.6V, 4000mAh Ni-CD cell that replaces the AK-58 battery in ARSEL emergency lighting units. It fits the AK-468-1, AK-468-2, AK-468-3, AK581, and eight additional models in the same range. The cell slots into the fitting and connects to the existing charge controller without modification.

• AK-468 and AK581 platform fit: These models share the same 3.6V single-cell architecture, connector format, and charge controller float voltage. One cell design covers the full range because the BMS handshake and trickle charge threshold are identical across all variants.
• Bench tested on actual hardware: We ran this cell through a full charge cycle and applied a load discharge to verify BMS cutoff at the correct low-voltage threshold. The cell held rated capacity and the protection circuit tripped within spec at the end of discharge.
• 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 and lets the charge controller register the new cell before the next scheduled compliance inspection.

Charge indicator staying red after new battery installation

A Ni-CD cell that has been in storage for several months arrives with a resting voltage below the charge controller's float acceptance window. The controller reads this as a fault state rather than a dischargeable cell, so the charge LED stays red and the trickle charge circuit may not engage. Leave the fitting powered for 12–24 hours — most ARSEL controllers will begin charging once the cell voltage climbs above approximately 3.0V through residual current. If the LED has not turned green after 24 hours, confirm mains supply to the fitting and check the cell connector seating.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-CD cell rarely delivers full rated capacity on the first test cycle. Ni-CD chemistry requires one complete charge and full-load discharge to reach rated capacity — a cell installed and tested the same day will often cut out before the test duration completes. Allow at least 24 hours of continuous mains charging before conducting a timed duration test. If the light still fails after a full conditioning cycle, verify the cell is 4000mAh and that the fitting's trickle charge voltage is within the 3.6V nominal range.