About this replacement
LUMINOX Planet D Series — 4.8V Ni-CD Replacement Battery (MGN74111)
This is a 4.8V, 800mAh Ni-CD replacement cell for the LUMINOX Planet D emergency lighting range. It fits the Planet D, Planet 60 D, LUM17002, and LUM17003 units. Swap it when the existing cell no longer holds charge or the fitting fails its duration test.
- Planet D and Planet 60 D compatibility: These fittings share the same charge controller board, 4.8V cell voltage, and physical bay dimensions. The BMS expects a nominal 4.8V Ni-CD pack — swapping chemistry to NiMH here will cause charge controller misreads and failed duration tests.
- Bench tested on actual hardware: We ran this cell through a full charge cycle and a load test at rated current. The BMS accepted the cell voltage, charge current stabilised within the expected window, and the fitting transitioned correctly from charging to float state.
- First-cycle activation on reinstalled fittings: On fittings returned to service after a long dormancy, hold the test button for the full rated duration within 24 hours of installation. This confirms the cell accepts load and lets the charge controller register the new capacity before the next scheduled compliance test.
Charge indicator staying red after new cell installation
A new Ni-CD cell shipped from storage typically sits at a lower resting voltage than the charge controller's float acceptance window. Some Planet D charge boards interpret this as a fault rather than a normal low-voltage start state. Leave the fitting powered for 12–16 hours. If the indicator is still red after that period, check that the cell connector is fully seated and the tab contacts are making clean metal-to-metal contact — a partial connection holds the cell voltage artificially low at the controller input.
Emergency light dims and cuts out partway through a duration test
This happens when a new cell is tested before it has completed at least one full charge cycle. Ni-CD cells shipped in a partially discharged state do not deliver rated capacity on the first draw. The fitting dims because cell voltage drops below the LED driver's minimum input rail before the test duration is complete. Charge the fitting for a full 24 hours, then rerun the duration test — the cell will deliver its rated 800mAh on the second cycle.