This paper summarizes battery modeling capabilities in ADVISOR—the National Renewable Energy Laboratory’s advanced vehicle simulator written in the Matlab/Simulink environment. ADVISOR’s Matlab-oriented battery models consist of the following: (1) an internal resistance model, (2) a resistance–capacitance (RC) model, (3) a PNGV capacitance model, (4) a neural network (nnet) lead acid model, and (5) a fundamental lead acid battery model. For the models, the electric schematics (where applicable), thermal models, accuracy, existing datasets, and sample validation plots are presented. A brief summary of ADVISOR’s capabilities for co-simulation with Saber is presented, which links ADVISOR with Saber’s lead acid battery model. The models outlined in this paper were presented at the workshop on ‘Development of Advanced Battery Engineering Models’ in August 2001.