Pansan 5020 Emergency Light Replacement Battery 3.6V 2000mAh

Pansan 5020 / 5020-C — 3.6V Ni-MH Replacement Battery (90703801)

This is a 3.6V, 2000mAh Ni-MH cell that replaces OEM part 90703801 in Panasonic emergency lighting units. It fits the 5020 and 5020-C fittings — the units mounted in commercial corridors, stairwells, and exit routes. Swapping this cell restores the fitting's ability to hold a charge and illuminate during mains failure.

• 5020 and 5020-C compatibility: Both models share the same charge controller circuit, connector orientation, and voltage rail. The BMS in these fittings floats at 3.6V nominal, so a mismatched cell chemistry or voltage will trigger a permanent fault LED — this Ni-MH cell matches that spec exactly.
• Bench tested on actual hardware: We ran this cell through a full charge cycle and a simulated mains-failure draw. The BMS accepted the cell without fault, the charge indicator moved to green within the expected window, and the cell held voltage under load without dropout.
• First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. This confirms the cell accepts load under real conditions and lets the charge controller register the new cell before your next scheduled compliance inspection.

Charge indicator staying red after fitting the new cell

The charge controller in the 5020 series uses a float voltage window to confirm a healthy cell is connected. A new Ni-MH cell that has been in storage will often sit below that acceptance threshold — typically under 3.4V resting. The controller reads this as a fault rather than a charge state, so the indicator stays red even though the cell is good. Leave the fitting connected to mains for 12–24 hours without triggering a test. Once the cell climbs above 3.5V, the controller re-evaluates and the indicator shifts to green.

Emergency light dims and drops output partway through a duration test

This happens when the cell has not completed a full conditioning charge before the test is run. A freshly installed Ni-MH cell does not reach full capacity on the first charge cycle — it typically needs one complete charge-discharge pass to settle at rated capacity. If a test is triggered too early, the cell voltage sags under load and the fitting's driver circuit reduces output to protect the cell. Allow a minimum 24-hour charge on mains before running any timed duration test, then perform the full hold-down test at rated load to confirm the cell delivers correctly.