Research and development of electric weapons is currently in progress in several countries for their benefits of higher muzzle velocities and insensitive munitions compared with conventional chemical guns. The integration of these weapons aboard land based vehicles will likely require careful consideration of the energy balances and power flows to all of the major loads aboard. Leveraging against ongoing research in electric drive trains capitalizes on a common power system bus and sharing of prime power between these loads, and such conceptual vehicles are classified as "all electric". Early conceptual studies of "all electric" vehicle power systems under the complex dynamic loadings experienced in real mission profiles are needed to optimally configure and size their components. This paper describes a power simulation model built in the Matlab/ Simulink programming environment, which allows these early studies to be rapidly conducted. This tool can also be used to evaluate the relative penalty in mobility and firepower performance for degradation in selected component characteristics, thus highlighting weak links in the power system architecture. An example case study is presented showing the influence of reduced weapon pulsed energy storage on the mobility and firing performance of the vehicle in an offensive type mission profile.