A four-stage power distribution system (100) includes (i) a first stage (110) having an inverter (112) that provides power to a frequency drive (114) and an electric motor (116) controlled by the frequency drive; (ii) a second stage (120) having a flywheel (122) driven by the motor; (iii) a third stage (130) having an alternator (132) driven by the motor (116) and connected to the flywheel, and a rectifier (134) that receives current from the alternator and generates a direct current; and (iv) a fourth stage (140) having a charge control switch (142) that receives power from the rectifier, and a plurality of power storage devices such as batteries (144A-144C). A master control switch (150) controls the charge control switch to transition the plurality of batteries individually between a charging configuration and a load configuration. One or more of the battery(ies) in the load configuration provides power to the inverter.