Schneider OVA51106 Replacement Battery 4.8V 800mAh Ni-CD

Schneider OVA51106 / Exiway EasyLED — 4.8V Ni-Cd Replacement Battery (4BD-AA800BT)

This is a 4.8V, 800mAh Ni-Cd replacement cell pack for Schneider Electric emergency lighting units. It fits the OVA51106, OVA51107, Exiway EasyLED, and OVA38352 series, along with several additional compatible fixtures. Swap it when the existing cell has lost charge retention or the unit no longer sustains illumination during a mains failure test.

• OVA51106 / OVA51107 / Exiway EasyLED platform fit: These fittings share the same 4.8V charge rail, connector pinout, and float charge profile. The BMS in each unit expects a Ni-Cd cell — substituting a different chemistry will cause the charge controller to misread cell voltage and either overcharge or refuse to charge entirely.
• Bench tested on actual hardware: We ran this cell on the OVA51106 charge circuit and confirmed the BMS accepted the cell within the float window, the charge indicator transitioned correctly, and the cell held load through a full simulated duration cycle without thermal cutoff.
• First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. Ni-Cd cells from storage have suppressed capacity until the charge controller runs one complete charge-discharge cycle. Skipping this step before a compliance inspection is the single most common reason a new cell fails a duration test.

Charge indicator staying red after fitting a new cell

The OVA51106 charge controller checks incoming cell voltage before entering float charge mode. A Ni-Cd cell stored for several months can sit below the acceptance threshold — typically under 4.2V open circuit — causing the controller to flag a fault rather than begin charging. In most cases, applying a brief manual test cycle forces the controller to push current into the cell, which lifts the resting voltage above the acceptance window. If the indicator does not shift to green within two hours of that cycle, measure cell voltage directly — a reading below 3.8V after a charge attempt points to a failed cell, not a wiring issue.

Emergency light dims noticeably partway through a duration test

This is not a faulty cell — it is a conditioning gap. Ni-Cd cells shipped from storage have not completed a full charge cycle, so usable capacity on the first draw is lower than rated. The fitting pulls rated current, the cell voltage sags under load, and the LED driver dims or cuts back output to compensate. One full 24-hour charge followed by a complete test cycle resolves this on the vast majority of units. After that conditioning cycle, the cell should sustain full output to the end of the rated duration without voltage sag below 4.0V under load.