About this replacement
Stahl ECOLUX 6608/5 — 6V Ni-CD Replacement Battery (118017)
This is a 6V 8000mAh Ni-CD replacement battery for the Stahl ECOLUX 6608/5 emergency lighting unit. It matches OEM part number 118017 and fits directly into the original fitting. The ECOLUX 6608/5 is a maintained or non-maintained emergency exit light — this battery is the cell that powers the lamp during a mains failure event.
- ECOLUX 6608/5 fit: The 6608/5 uses a fixed 6V Ni-CD cell with specific float charge acceptance requirements. The charge controller in this fitting monitors cell voltage and will not register a healthy state until the cell climbs into its float acceptance window — a mismatched cell type or voltage rating trips a fault condition immediately.
- Bench tested on actual hardware: We ran this cell through a full charge cycle on a Ni-CD controlled charger and confirmed the BMS accepted the float voltage without fault. Load discharge confirmed the cell held capacity through a full simulated test duration without voltage collapse.
- First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. This forces the charge controller to register the new cell's capacity baseline before the next scheduled compliance test. Skipping this step can cause the fitting to log a duration failure on its first automatic test.
Charge indicator staying red after fitting a new 118017 cell
The ECOLUX 6608/5 charge controller monitors float voltage to confirm the cell is healthy. A new Ni-CD cell that has been in storage will often arrive at a suppressed resting voltage — sometimes below the controller's float acceptance threshold. The controller reads this as a fault and holds the red LED. Allow the fitting to trickle charge the new cell for 24 hours undisturbed; most cells recover to float voltage within that window and the indicator shifts to green. If the LED stays red beyond 48 hours, measure the cell terminal voltage — it should be climbing toward 7.2V on a 6V Ni-CD pack under charge.
Emergency light dims partway through a duration test after battery replacement
A new Ni-CD cell that hasn't completed a full conditioning cycle will show voltage sag under sustained load before the test duration ends. This is not a cell defect — it reflects that the cell hasn't yet reached its rated capacity from storage. The fix is one complete charge-discharge-charge cycle: run the test button to full discharge, then charge uninterrupted for a full cycle before the next test. After that cycle, the cell's available capacity aligns with its 8000mAh rating and voltage holds stable across the full test duration.