Teknoware ESC 90 Emergency Exit Light Replacement Battery 4.8V 1200mAh

Teknoware ESC 90 Emergency Exit Light — 4.8V Ni-MH Replacement Battery (W120011)

This is a 4.8V, 1200mAh Ni-MH replacement battery for the Teknoware ESC 90 Emergency Exit Light. It fits units listed under part numbers W120011, XWT9001, and EA051. The battery powers the exit sign during mains failure, keeping the lamp lit for the rated emergency duration required by building compliance codes.

• ESC 90 and XWT9001/EA051 compatibility: These variants share the same 4.8V cell pack configuration, connector pin-out, and charge controller handshake. A single cell format covers all three part number references without modification.
• Bench tested on actual hardware: We cycled this pack through a simulated mains-failure event on the ESC 90 charge board. The BMS accepted the charge handshake immediately, and the cell voltage held stable under lamp load through the full test duration.
• First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. This lets the charge controller register the new cell capacity and confirms load acceptance before your next scheduled compliance inspection.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-MH cell ships in a partial state of charge — typically between 30% and 60% of rated capacity. The ESC 90 charge controller uses a trickle charge profile, so the cell needs a full 24-hour charge period before it can deliver the rated 1200mAh under lamp load. Running a duration test immediately after installation will produce a short runtime result that does not reflect the battery's actual capacity. Allow a full charge cycle first, then run the test.

Charge indicator staying red after new battery installation

The ESC 90 charge controller checks cell voltage at float acceptance before switching the indicator to green. A cell that has sat in storage for several months may present a resting voltage outside that acceptance window, causing the controller to hold the fault state. Leave the fitting powered for at least 12 hours — the trickle charge will bring the cell voltage up into the acceptance range. If the indicator remains red after 24 hours, check the cell connector seating and confirm terminal voltage reads at or above 4.0V with a multimeter.