A backup power system (100, 400), the system comprising: a secondary power source; a stored energy component capable of storing energy therein; and a controller in data communication with the secondary power source and the stored energy component, wherein said controller is configured to: compare a measured energy level of energy stored within the stored energy component against a first threshold determined by a maximum time necessary for the secondary power source to at least reach a selected minimum power output level, wherein the first threshold is selected so as to ensure that the secondary power source may be brought into service to power the external load powered by the backup power system (100, 400) using less than an amount of power remaining in the stored energy component, and compare the stored energy level to a second threshold greater than the first threshold, said second threshold being selected so as to reduce a number of on/off cycles of the secondary power source during periods of intermittent power fluctuations of a primary power source, said controller being controlled and arranged so as to selectively provide power to the external load from one of a primary power source, the secondary power source, and the stored energy component in response to the comparison with either the first threshold or the second threshold. a secondary power source; a stored energy component capable of storing energy therein; and a controller in data communication with the secondary power source and the stored energy component, wherein said controller is configured to: compare a measured energy level of energy stored within the stored energy component against a first threshold determined by a maximum time necessary for the secondary power source to at least reach a selected minimum power output level, wherein the first threshold is selected so as to ensure that the secondary power source may be brought into service to power the external load powered by the backup power system (100, 400) using less than an amount of power remaining in the stored energy component, and compare the stored energy level to a second threshold greater than the first threshold, said second threshold being selected so as to reduce a number of on/off cycles of the secondary power source during periods of intermittent power fluctuations of a primary power source, said controller being controlled and arranged so as to selectively provide power to the external load from one of a primary power source, the secondary power source, and the stored energy component in response to the comparison with either the first threshold or the second threshold. compare a measured energy level of energy stored within the stored energy component against a first threshold determined by a maximum time necessary for the secondary power source to at least reach a selected minimum power output level, wherein the first threshold is selected so as to ensure that the secondary power source may be brought into service to power the external load powered by the backup power system (100, 400) using less than an amount of power remaining in the stored energy component, and compare the stored energy level to a second threshold greater than the first threshold, said second threshold being selected so as to reduce a number of on/off cycles of the secondary power source during periods of intermittent power fluctuations of a primary power source, said controller being controlled and arranged so as to selectively provide power to the external load from one of a primary power source, the secondary power source, and the stored energy component in response to the comparison with either the first threshold or the second threshold.