The virtual test bed (VTB) computation environment provides an easy-to-use way for electric system modeling and simulation. Resistive companion (RC) modeling of batteries in VTB is presented in the paper. Native RC battery modeling approach and the one using current controlled voltage source (CCVS) interface are presented and compared through two battery models with different degrees of complexity. The RC battery models are validated by comparing VTB simulation data to those calculated directly through stand-alone Fortran codes. It is concluded that using CCVS interface is currently the first choice in modeling batteries in VTB. Simulations using the RC battery models in VTB are also presented and analyzed. It is shown that RC modeling provides a powerful way for the simulation of battery systems in VTB. (c) 2004 Elsevier B.V. All rights reserved.