Abstract: An apparatus and method for initiating an intelligent battery discharge in an electrical system thereby allowing battery diagnostic testing to be performed more efficiently and more accurately. Specifically, the discharge is initiated by reducing the voltage being supplied to the electrical system by a main power supply such that the battery power supply begins supplying the system voltage. The output of the main power supply is only reduced to a predetermined non-zero level, such that the battery power supply will begin discharging while the main power supply continues to maintain a floor voltage. This floor voltage ensures that the system voltage will not fall below the floor voltage even if the battery power supply fails completely. Once the battery power supply begins discharging, the system voltage is monitored to determine whether the battery power supply is capable of supplying sufficient electrical power to maintain the system voltage above the floor voltage.