URA 131607 Emergency Light Replacement Battery 3.6V 4000mAh

URA 131607 / 137973 / 186003 — 3.6V Ni-CD Replacement Battery (MXN0050)

This is a 3.6V, 4000mAh nickel-cadmium cell built to replace the MXN0050 battery in URA emergency lighting units. It fits the 131607, 137973, 186003, 615910, and at least eleven additional URA models that share the same charge controller circuit and connector format. Capacity figure is 4000mAh as specified — do not use a lower-rated cell as a substitute.

• Multi-model fit across URA emergency lighting range: These URA fittings share a common trickle-charge topology and cell footprint. The charge controller floats at a fixed voltage, so cell chemistry, physical dimensions, and terminal orientation all have to match — this cell does on every count across the listed models.
• Bench tested on actual hardware: We ran this cell through a full charge cycle and a simulated mains-fail discharge event. The BMS accepted the cell without a fault state, and the fitting registered the correct float voltage at the terminals within the expected window.
• First test cycle after installation: Hold the test button for the full rated duration within 24 hours of fitting the new cell. This lets the charge controller register the new cell's capacity and confirms load acceptance before your next scheduled compliance inspection.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-CD cell does not arrive at full capacity. Storage partially depletes the cell, and the charge controller needs at least one complete charge-discharge cycle before the cell reaches its rated 4000mAh. Running a duration test immediately after installation will almost always result in a short runtime. Allow the fitting to charge uninterrupted for 24 hours before testing. After that first full cycle, the cell should meet the rated duration at 3.6V under load.

Charge indicator staying red after new cell installation

Some URA fittings reject a new cell if its resting voltage falls outside the float acceptance window — a cell that has been in storage for months can read low enough to trigger a fault state. The charge controller interprets this as a damaged or missing cell rather than a discharged one. Leave the fitting powered on for two to four hours; the controller should step out of fault mode once the cell voltage climbs above the acceptance threshold. If the red indicator persists beyond four hours, check the terminal connections and confirm the cell voltage at the terminals reads at or above 3.0V.