A system and method for optimizing a plug-in vehicle fleet having a plurality of battery packs across the vehicle fleet. Each vehicle includes a battery pack. The system includes sensors for measuring battery performance data and includes an open-circuit voltage, charging current, and/or temperature of the battery pack, a GPS receiver, a user interface, and a controller. The controller executes a method to monitor degradation of each battery pack using a variety of current and historical data points. The controller then controls a charging operation of each battery pack in a fleet via a charging control signal sent to a particular vehicle in the fleet. The controller also then determines the new location for each particular vehicle in a fleet.