Legrand 806525 Emergency Lighting Compatible Battery 2.4V 800mAh

Legrand 806525 / ST1 F200 BAES — 2.4V Ni-CD Replacement Battery (MXN0067, MXN0082)

This is a 2.4V 800mAh Ni-CD replacement battery for Legrand emergency lighting units, specifically the 806525, ST1 F200, and BAES 806525 fittings. It slots into the fitting's battery compartment and connects to the on-board charge controller that keeps the cell in float between mains-power events. Voltage and cell geometry match the OEM specification for these units.

• 806525, ST1 F200, and BAES 806525 compatibility: These three Legrand fittings share the same 2.4V charge rail, the same physical cell footprint (50.20 × 28.20 × 14.10mm), and the same two-wire connector orientation — so a single cell covers all three without any modification.
• Bench tested on actual hardware: We connected this cell to a Legrand 806525 charge controller and monitored BMS float acceptance. The controller registered charge current within two minutes of connection and transitioned to float at the expected voltage window without fault.
• First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. Ni-CD cells that have been in storage need one complete load cycle before the charge controller can accurately register cell capacity — skipping this step can cause a false fail on your next compliance inspection.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-CD cell does not arrive at full capacity — storage self-discharge leaves it partially depleted. The charge controller in the 806525 fitting applies a trickle charge, but it takes up to 24 hours to bring a new cell to its rated 800mAh from a storage state. If a compliance duration test runs before that charge cycle completes, the light will cut out early and log a fail against a battery that is otherwise functional. Run a full manual test cycle after the first 24-hour charge period to confirm the cell holds load before any scheduled inspection.

Charge indicator staying red after new battery installation

The charge controller on these Legrand fittings reads cell voltage before accepting it into the float window. A cell that has dropped below approximately 1.8V during long storage sits outside the float acceptance threshold, so the controller continues showing a fault or red LED rather than transitioning to green. The fix is to leave the fitting powered on the mains for a full 24-hour conditioning period — the controller applies a recovery charge that brings cell voltage back into the 2.4V nominal range. After that period, the indicator should shift to green; if it does not, check that the connector is fully seated and measure cell voltage directly — it should read at or above 2.2V under no load.