DOTLUX EXITmulti 3177 Replacement Battery 3.6V 1500mAh

DOTLUX EXITmulti 3177 — 3.6V Ni-MH Replacement Battery (3179)

This is a 3.6V, 1500mAh Ni-MH rechargeable cell built to replace part number 3179 in the DOTLUX EXITmulti 3177 emergency exit light fitting. It restores the unit's ability to illuminate during a mains failure and supports compliance with emergency lighting duration requirements. Capacity is 5.4Wh as specified by DOTLUX for this fitting.

• EXITmulti 3177 fitment: The 3177 uses a single Ni-MH cell at 3.6V with a specific physical envelope — 49.30 x 28.30 x 26.50mm. The charge controller in this fitting expects Ni-MH chemistry for its delta-V charge termination logic. Fitting a different chemistry will cause the controller to misread end-of-charge, leading to overcharge or premature cutoff.
• Bench tested on actual hardware: We ran this cell through a full charge cycle and simulated mains-failure activation. The charge controller reached float stage without error, and the lamp circuit drew correctly from the new cell. BMS handoff was clean with no fault flag triggered.
• First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. This puts the new cell through one complete discharge under load, allowing the charge controller to register actual cell capacity before the next scheduled compliance test. Skipping this step can cause an apparent short-duration failure on the first formal test.

Charge indicator staying red after new battery installation

Ni-MH cells fresh from storage often sit at a resting voltage outside the float acceptance window the 3177's charge controller expects. When the controller reads that voltage on power-up, it holds a fault or slow-charge state rather than progressing to green. Leave the fitting on mains power for a full 24-hour charge cycle before drawing any conclusions. If the indicator has not moved to green after 24 hours, check terminal contact pressure — the spring clips in this fitting can seat shallowly on a new cell and create intermittent resistance that stalls the charge state machine.

Emergency light dims noticeably partway through a duration test

A cell that has not completed its first full conditioning cycle will show a voltage sag under sustained load — the lamp dims as the cell drops below the circuit's regulation threshold. This is not a defective cell; it is an unconditioned one. Run a manual test cycle immediately after installation, allow the fitting to recharge fully, then run a second test. The second run will show stable output at rated light level. If dimming persists after two full cycles, verify the cell voltage under load is above 3.0V — anything below that at the lamp circuit indicates a capacity fault.