Mackwell B613 Emergency Light Replacement Battery 2.4V 8000mAh

Mackwell B613 / B624 / B824 Series — 2.4V Ni-MH Replacement Battery

This is a 2.4V, 8000mAh Ni-MH replacement cell for Mackwell emergency lighting units including the B613, B613/24, B624, and B824. It fits directly into the battery compartment of these self-contained emergency luminaires and maintained exit signs. Capacity is rated at 19.2Wh — sufficient to meet the charge reserve required for standard duration compliance tests.

• B613, B613/24, B624, B824 platform: These fittings share the same 2.4V battery rail and physical cell envelope. The charge controller in each unit expects a Ni-MH cell within a specific voltage window at float — this cell meets that window, so the controller will cycle normally without triggering a fault state.
• Bench tested on actual hardware: We ran this cell through a full charge cycle and discharge load test. The cell accepted charge cleanly, held voltage under load without dropping below the controller cutoff threshold, and the charge indicator transitioned to green within the expected timeframe.
• First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. This confirms the cell accepts load and lets the charge controller register the new cell capacity before your next scheduled compliance inspection.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-MH cell does not arrive at full capacity — storage and shipping drain it below the float threshold the charge controller expects. If a duration test is run too soon after installation, the cell cannot sustain the lamp load for the full rated period and the fitting will fail the test. The charge controller needs time to bring the cell up to a proper state of charge before any test is valid. Allow at least 24 hours of uninterrupted mains charging after installation before running a duration test. After one full conditioning cycle, the cell should hold voltage above 2.0V throughout the rated test period.

Charge indicator staying red after new battery installation

The charge controller on Mackwell B-series fittings monitors cell voltage at the float charge point — if the incoming voltage sits below the acceptance window, the controller reads a fault and the LED stays red. A depleted cell fresh from storage can present a voltage low enough to trigger this. Leave the fitting on mains for a minimum of 24 hours. If the LED remains red after that period, disconnect the battery connector, wait 10 seconds, and reconnect — this resets the fault latch on most B-series controllers. The LED should transition to green once the cell climbs above approximately 2.3V.