A method of balancing the state of charge of a plurality of energy storage modules in a vehicle using a controller, the vehicle being configured to be driven by an electric motor, comprising: determining states of charge of individual energy storage modules in said plurality of energy storage modules, wherein said energy storage modules are operatively connected in parallel to an inverter in the vehicle and include contactors configured to selectively electrically connect each individual energy storage module to the inverter in the vehicle; selecting a first energy storage module for discharge when the state of charge of said first energy storage module is greater than or equal to a tolerance relative to the remaining energy storage modules of said plurality of energy storage modules; characterized by: selecting a second energy storage module when the state of charge of said second energy storage module is greater than or equal to a tolerance relative to the remaining energy storage modules of said plurality of energy storage modules and less than a state of charge of said first energy storage module; engaging the contactors for the first energy storage module to electrically connect the first energy storage module to operate the vehicle using the first energy storage module, wherein said vehicle operation includes partially discharging the first energy storage module to assist in propulsion of the vehicle; wherein the vehicle is operated using said first energy storage module until the state of charge of the first energy storage module is substantially equal to said second energy storage module; and engaging the contactors for the first and second energy storage modules to electrically connect the first and second energy storage modules to provide power to the vehicle using the first and second energy storage modules. determining states of charge of individual energy storage modules in said plurality of energy storage modules, wherein said energy storage modules are operatively connected in parallel to an inverter in the vehicle and include contactors configured to selectively electrically connect each individual energy storage module to the inverter in the vehicle; selecting a first energy storage module for discharge when the state of charge of said first energy storage module is greater than or equal to a tolerance relative to the remaining energy storage modules of said plurality of energy storage modules; characterized by: selecting a second energy storage module when the state of charge of said second energy storage module is greater than or equal to a tolerance relative to the remaining energy storage modules of said plurality of energy storage modules and less than a state of charge of said first energy storage module; engaging the contactors for the first energy storage module to electrically connect the first energy storage module to operate the vehicle using the first energy storage module, wherein said vehicle operation includes partially discharging the first energy storage module to assist in propulsion of the vehicle; wherein the vehicle is operated using said first energy storage module until the state of charge of the first energy storage module is substantially equal to said second energy storage module; and engaging the contactors for the first and second energy storage modules to electrically connect the first and second energy storage modules to provide power to the vehicle using the first and second energy storage modules. selecting a second energy storage module when the state of charge of said second energy storage module is greater than or equal to a tolerance relative to the remaining energy storage modules of said plurality of energy storage modules and less than a state of charge of said first energy storage module; engaging the contactors for the first energy storage module to electrically connect the first energy storage module to operate the vehicle using the first energy storage module, wherein said vehicle operation includes partially discharging the first energy storage module to assist in propulsion of the vehicle; wherein the vehicle is operated using said first energy storage module until the state of charge of the first energy storage module is substantially equal to said second energy storage module; and engaging the contactors for the first and second energy storage modules to electrically connect the first and second energy storage modules to provide power to the vehicle using the first and second energy storage modules.