PowerSonic OSA129 6V Emergency Light Replacement Battery 8000mAh

PowerSonic A13146-4 — 6V Ni-CD Replacement Battery (OSA129)

This is a 6V, 8000mAh Ni-Cadmium replacement battery for the PowerSonic A13146-4 emergency lighting unit. It slots into the existing fitting and restores backup illumination when mains power fails. Dimensions are 162.00 x 92.00 x 32.70mm — confirm these against your fitting before ordering.

• A13146-4 compatibility: The A13146-4 uses a 6V Ni-CD cell at this exact form factor. The charge controller in this fitting expects Ni-CD chemistry — a Li-ion swap at the same voltage will misread the charge curve and either undercharge or trigger a fault LED.
• Bench tested on actual hardware: We ran this cell through a full charge cycle and a load discharge on the bench. The BMS accepted the cell without fault, float voltage settled correctly, and the charge indicator moved to green within the expected window.
• First-cycle test requirement: Within 24 hours of installation, hold the test button for the full rated duration. This lets the charge controller register the new cell's capacity and confirms the cell accepts load before your next scheduled compliance test.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-CD cell rarely delivers full rated capacity on its first discharge. Ni-CD cells shipped from storage have partially self-discharged, and the first charge cycle often only partially recovers the cell plates. The charge controller may not have run a full conditioning cycle before the test was triggered. Run one complete charge-then-discharge cycle — the test button held to full cutoff — before relying on the battery for a compliance duration test.

Charge indicator staying red after new battery installation

The A13146-4 charge controller checks incoming cell voltage before entering float mode. A cell that has sat in storage below approximately 5.4V sits outside the controller's float acceptance window, and the indicator stays red. Leave the fitting on mains power for a full 24-hour charge before testing. If the indicator is still red after 24 hours, measure cell voltage directly — a cell reading below 4.8V after a full charge cycle has likely suffered storage damage and will not recover.