For the latest military vehicles being developed with high-voltage, on-board power generation systems, compliance with MIL-PRF-GCS600A(ARMY) is a prerequisite for vehicle bus stability. The primary component responsible for stability is the generator/controller. As part of MIL-PRF-GCS600A, the voltage regulation requirements for the generator sub-system can be validated in the laboratory. However, determining overall vehicle electrical system compliance before prototype integration is more difficult. The individual loads on the bus may not be available for laboratory integration and testing. Likewise, the vehicle prime mover, an internal combustion engine (ICE), may not be available. Assessing compliance to MIL-PRF-GCS600A during the sub-system development phase, prior to vehicle build, can aid in optimization of the electrical system, i.e. vehicle bus capacitance sizing and allocation. Vehicle electrical system compliance can be assessed using high fidelity generator/controller models together with ICE and load models. Various load duty cycles and fault conditions can be simulated and evaluated with respect to MIL-PRF-GCS600A. With its two world class laboratories, the Motor Testing Laboratory and the new Ground Systems Power and Energy Laboratory (GSPEL), the US Army Tank Automotive Research, Development and Engineering Center (TARDEC) is uniquely equipped to perform characterization and testing of high-voltage vehicle generator systems. Generator testing to MIL-PRF-GCS600A is part of TARDEC’s standard electrical machine testing and characterization procedures. From testing and characterization results, high fidelity models are developed and validated.