About this replacement
Zumtobel 0072883 — 2.4V Ni-MH Replacement Battery (249Cx2)
This is a 2.4V 5000mAh Ni-MH replacement cell for the Zumtobel 0072883 emergency lighting fixture. It fits units listed under part references 249Cx2, 59 004 665, and 9008709501379. The cell powers the backup illumination circuit when mains supply fails, keeping exit signs and safety lighting live for the duration required under compliance testing.
- 0072883 fitting compatibility: These Zumtobel fixtures run a 2.4V charge rail with a float voltage the internal controller maintains continuously. The 249Cx2 cell format matches the physical footprint at 51.60 × 51.60 × 26.00mm and connects directly to the charge circuit without adapters or wiring changes.
- Bench tested on actual hardware: We ran the cell through a full charge cycle and a load discharge at the rated output. The BMS accepted the cell immediately, floated correctly at rest, and the cell held voltage under load without dropping below the controller's low-voltage cutoff threshold.
- First-cycle test requirement: Run a manual test within 24 hours of installation by holding the test button for the full rated duration. A Ni-MH cell coming out of storage does not start at full capacity — one complete charge-discharge cycle lets the controller register actual cell capacity before your next scheduled compliance inspection.
Charge indicator staying red after fitting a new 249Cx2 cell
Zumtobel emergency fittings float the cell at a tightly controlled voltage. A cell stored for several months arrives with a resting voltage that sits outside that acceptance window, which causes the charge controller to hold the fault state rather than transition to green. The fix is to leave the fitting on mains for 24 to 48 hours uninterrupted — the controller will step the cell voltage up gradually until it falls within the float acceptance range. If the indicator is still red after 48 hours, check that the cell connector is fully seated and that terminal voltage at the cell tabs reads at least 2.2V.
Emergency light dims noticeably partway through a duration test
A new Ni-MH cell that has not completed a full conditioning cycle cannot sustain rated capacity under continuous load. The fitting draws current at a steady rate through the test, and a partially conditioned cell sags in voltage before the test period ends, causing visible dimming. This is not a faulty cell — it is a cell that needs one complete charge and discharge cycle to reach rated capacity. Allow a full 24-hour charge after installation, then run the duration test again from a fully charged state.