A novel test protocol is proposed for fuel cells that are in a nonfunctioning or passive state. Standard fuel-cell test methods are reviewed, along with the equivalent circuit models (ECMs) used to represent functioning or active fuel cells. Standard active tests focus on single cells, while the passive test is shown to be applicable to testing multiple cells. The passive test measures electrical characteristics of the fuel cell in the absence of electrochemical reactions. A simple ECM is developed to describe the cell behavior under the passive test conditions. Circuit model parameters of many series-connected cells can be acquired using the results of a single stack test. Proton exchange membrane fuel cells (PEMFCs) from three manufacturers were tested, ranging in system power from 12-500 W. Test results for each PEMFC exhibited similar behavior that is well predicted by the ECM. A strong similarity between a passive fuel cell and a double layer capacitor is discussed.