An emergency lighting supervisory system monitors utility power so as to automatically connect emergency lights to a battery source when utility power fails. The system continuously monitors selected parameters and, automatically, periodically tests the system under simulated full-load emergency conditions and annunciates the results of these tests. Such periodic tests also enhance the battery capacity. The system also provides a closed loop three-mode battery charging control circuit. It can optionally communicate its status as well as receive commands from an external computer or other source by means of a data communication interface.