About this replacement
DOTLUX EXIT / 5389 — 3.2V LiFePO4 Replacement Battery (5395)
This is a 3.2V, 3000mAh lithium iron phosphate cell for the DOTLUX EXIT emergency lighting fixture (model 5389). It replaces OEM part 5395 when the original cell can no longer hold sufficient charge to power the exit sign through a full test duration. At 9.6Wh, it matches the energy specification the fitting's charge controller expects.
- EXIT and 5389 fitting compatibility: Both the EXIT and 5389 share the same 3.2V LiFePO4 cell format, connector pinout, and charge controller voltage window. The BMS accepts float charge from the fitting's onboard circuit without requiring any hardware change.
- Bench tested on actual hardware: We cycled this cell through charge and full load discharge on the bench. The BMS held stable across the charge curve, and the cell reached rated capacity within one full conditioning cycle.
- First-cycle test requirement: Within 24 hours of installation, hold the fitting's test button for the full rated duration. This confirms the new cell accepts load and allows the charge controller to register the cell before the next scheduled compliance test.
Emergency light failing its duration test after battery replacement
A freshly installed LiFePO4 cell ships at partial state of charge — typically 40–60% — to meet transport safety rules. The fitting's charge controller needs at least one full charge cycle before the cell reaches its rated 3000mAh capacity. Running a duration test immediately after installation will almost always produce a shorter runtime than expected. Allow a full 24-hour charge on mains before the first compliance test, then trigger the test manually.
Charge indicator staying red after fitting a new cell
Some DOTLUX EXIT fittings latch a fault state in the charge controller when the old cell voltage drops below the float acceptance window. Fitting a new cell does not automatically clear this latch. The controller sees the new cell's resting voltage — around 3.2–3.3V — but still holds the fault flag from the previous degraded cell. Disconnect mains power for 30 seconds, then reconnect. This forces the controller to re-initialise and read the new cell voltage fresh.