Light unit with internal power failure detection

A lighting apparatus, comprising:

• a power input configured to receive external power from an external power source
• a solid state light element that is interconnected to the power input;
• a detection circuit interconnected to the power input and that, when power is not provided to the power input, measures input impedance at the power input and determines if there is a lack of external power;
• a back-up power source that is interconnected to the solid state light element, the detection circuit, and the power input, that provides power to the solid state light element when the light element is not provided with power from the power input, and
• a microcontroller that is interconnected with the power input, solid state light element, and back-up power source, that controls the illumination of the solid state light element, wherein the microcontroller comprises a memory that has instructions stored therein that, when executed by the microcontroller, cause the microcontroller to illuminate the solid state light element using power from the power input or using power from the back-up power source.