About this replacement
Lumenxl OTG-KL Series — 3.6V Ni-CD Replacement Battery (OTG-KL-BAT)
This is a 3.6V, 2000mAh nickel-cadmium replacement battery for the Lumenxl OTG-KL emergency lighting unit. It fits the OTG-KL, OTG-KL-1, and OTG-EF-55 models and restores backup illumination capability after the original cell degrades. OEM part number OTG-KL-BAT.
- OTG-KL, OTG-KL-1, and OTG-EF-55 fitment: All three models run the same 3.6V cell format, connector pitch, and charge controller voltage window. The BMS handshake on each accepts this cell without modification or adaptation.
- Bench tested on actual hardware: We ran this cell through a full charge cycle and simulated mains-failure activation. The charge controller accepted the cell voltage on first insertion and the BMS registered load correctly under emergency draw.
- First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. This confirms the new cell accepts load under real conditions and lets the charge controller register cell capacity before the next scheduled compliance test.
Emergency light failing its duration test after battery replacement
A new Ni-CD cell ships in a partially discharged state. The charge controller on the OTG-KL begins trickle charging on installation, but the cell needs at least one full charge cycle before it reaches rated capacity. Running a duration test too soon — before 24 hours of mains-connected charging — will produce a shorter-than-rated illumination period and trigger a compliance failure. Allow a full 24-hour charge before the first test, then run the button test to confirm the cell delivers its rated output.
Charge indicator staying red after new battery installation
The OTG-KL charge controller checks cell voltage on insertion. If the cell voltage sits outside the float acceptance window — common after extended storage — the controller holds the fault or charging state and the indicator stays red. This is not a wiring or fitment fault. Leave the unit on mains power for 24 to 48 hours. The controller will bring the cell up through its charge stages and switch to green once the cell reaches float voltage, typically around 4.2V for this 3.6V Ni-CD configuration.