The LEM04 emergency LED driver enables the lighting fixture to deliver a minimum of 90-minutes illumination during a loss of normal AC power. It is UL Listed for factory or field installation with indoor, damp location luminaires utilizing 20-Volt DC to 50-Volt DC output voltage. When normal AC power fails, the LEM04 immediately drives the LED load at reduced light output for a minimum of 90-minutes. When AC power is present, the emergency LED driver ensures the sealed, maintenance-free, high-temperature nickel-cadmium batteries are fully charged within 24-hours after a discharge and remains fully charged until the next loss of AC power. The included test switch/pilot light provides visual and manual means of monitoring the system operation.