A series battery start controller for starting an aircraft turbine engine and method thereof is provided, wherein the battery series start controller connects two batteries in series when an aircraft engine starter is engaged to provide a higher voltage to start the aircraft engine and to provide adequate operational voltage to aircraft engine instruments and other aircraft electrical systems, and wherein the battery series start controller reconnects the batteries in parallel when the electrical load drawn by the starting aircraft engine decreases and the supplied voltage to the aircraft rises to a predetermined threshold.