Saft 0120894-A Emergency Light Replacement Battery 4.8V 2000mAh

Saft 0120894-A — 4.8V Ni-MH Replacement Battery for Emergency Lighting

This Saft 4.8V 2000mAh Ni-MH battery replaces the 0120894-A cell pack used in emergency lighting units and exit sign fittings. It fits backup illumination systems that activate on mains failure in commercial buildings. Voltage and capacity match the original specification: 4.8V, 2000mAh (9.6Wh).

• Emergency lighting fitment: These fittings share a fixed 4.8V four-cell Ni-MH architecture. The charge controller floats the pack at a set voltage rail and monitors cell resistance — a mismatched chemistry or voltage will trigger a fault LED or prevent charge acceptance entirely.
• Bench tested on actual hardware: We ran this pack through a full discharge-charge cycle on an emergency lighting test rig. The BMS accepted charge without fault, float voltage settled within the controller's acceptance window, and the pack held load through a full duration draw without cell voltage collapse.
• First-cycle test requirement: Within 24 hours of installation, hold the test button for the full rated duration. This confirms the cell accepts load under real conditions and lets the charge controller register the new pack before any scheduled compliance test.

Charge indicator staying red after new battery installation

A replacement Ni-MH pack shipped from storage will have a resting voltage lower than the controller's float acceptance window. The charge controller reads this as a fault rather than a normal charge state. Leave the fitting on mains power for 24 hours — the controller will step through its conditioning phase and the indicator should move to green once the pack voltage climbs above the acceptance threshold. If the red LED persists past 48 hours, measure the pack voltage directly: it should read between 5.4V and 6.0V at full charge.

Emergency light dims partway through a duration test

Dimming mid-test almost always means the pack was not fully conditioned before the test ran. A freshly installed Ni-MH cell hasn't completed its first full charge cycle, so available capacity is below rated. The load draws the cell voltage down faster than expected and the fitting dims or cuts off early. Allow a minimum 24-hour charge before running any duration test, then rerun the full test from a fully charged state. A genuine capacity fault — cell not recovering after conditioning — will show pack voltage dropping below 4.0V under load.