About this replacement
Lithonia ELB1208 / ELB1208N — 12V 7000mAh Ni-Cd Replacement Battery (B310004)
This is a 12V 7000mAh Ni-Cd replacement battery for Lithonia ELB1208, ELB1208N, and OSA195 emergency lighting units. It replaces OEM part numbers B310004 and OSA052. These fixtures provide mandatory backup illumination during mains failure, so a functioning cell is a code requirement, not optional maintenance.
- ELB1208, ELB1208N, and OSA195 compatibility: All three models share the same charge controller circuit, connector pinout, and 12V Ni-Cd cell requirement. The charge controller expects a Ni-Cd charge curve — dropping a Li-ion cell into this fitting will trigger a fault state the controller cannot recover from.
- Bench tested on actual hardware: We cycled this cell through a simulated mains-drop test. The BMS accepted the load without tripping, voltage held stable through the discharge curve, and the charge controller moved to float without flagging a fault LED.
- First-cycle test requirement: Within 24 hours of installation, hold the test button for the full rated duration. This allows the charge controller to register the new cell capacity before your next scheduled compliance inspection — a cell pulled straight from storage may not pass a timed duration test until it has completed one full cycle.
Emergency light failing its duration test after battery replacement
A freshly installed Ni-Cd cell stored at low state of charge will not immediately deliver its full 7000mAh rated capacity. The charge controller in the ELB1208 uses a trickle charge circuit — it brings the cell up slowly, not to full capacity in the first hour. If you install and test the same day, the cell may cut out before the test duration completes. Allow a minimum 24-hour charge period after installation before running any compliance duration test. Target resting voltage before test should be at or above 13.8V across the pack terminals.
Charge indicator staying red after new battery installation
The ELB1208 charge controller checks incoming cell voltage before accepting charge. A cell that has been in storage below the controller's float acceptance window — typically under 10V for a 12V Ni-Cd pack — will cause the fault LED to stay red even when the battery is correctly installed. Remove the cell, measure open-circuit voltage with a multimeter, and confirm it reads above 10V. If it reads below that threshold, apply a short manual test-button press to draw a surface charge down and allow the controller to re-initialise its charge cycle from a known state.