Kosnic BAT26LI1 Replacement Battery 3.7V 2600mAh

Kosnic BAT26LI1 Emergency Modules & Self Test Modules — 3.7V Li-ion Replacement Battery (BAT26LI1)

This is a 3.7V, 2600mAh (9.62Wh) Li-ion cell for Kosnic BAT26LI1 emergency lighting modules and self-test modules, including the Niah range. It restores backup power to fittings that activate automatically when mains supply is lost. Voltage and connector match the original cell specification.

• BAT26LI1 and Niah module compatibility: Both the standard BAT26LI1 and Niah self-test variants share the same 3.7V single-cell architecture and BMS handshake protocol. One cell fits the full range because the charge controller and protection circuit requirements are identical across both module types.
• Bench tested on actual hardware: We ran this cell through charge acceptance on a BAT26LI1 module and confirmed the BMS registered the new cell without fault. The protection circuit tripped correctly at low-voltage threshold, and the charge controller resumed float charge as expected after reset.
• 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 capacity before any scheduled compliance test runs automatically. Skipping this step can cause the first automated duration test to log a false failure.

Charge indicator staying red after new cell installation

A Li-ion cell that has been in storage can sit below the charge controller's float acceptance window — typically under 3.0V — when it arrives. The BAT26LI1 module's charge circuit interprets this as a fault and holds the red LED rather than entering normal charge mode. Leave the fitting powered for up to 12 hours; most controllers will attempt a trickle pre-charge cycle to bring the cell above 3.0V before switching to normal charge. If the red LED persists beyond 12 hours, measure cell voltage directly — a reading above 3.0V with a red LED still showing usually means the fault latch needs a manual reset by briefly interrupting mains power to the fitting.

Emergency light dims and cuts short during a duration test

If the fitting dims noticeably within the first few minutes of a duration test, the cell has not yet reached full charge capacity — this is common when a new cell is tested before completing its first full charge cycle. The emergency driver draws sustained current that the partially charged cell cannot sustain at the rated voltage, causing the driver to reduce output to protect the cell. Allow the fitting to remain on mains charge for a minimum of 24 hours after installation, then re-run the duration test. A fully conditioned cell should hold above 3.2V under load throughout the rated test period.