The objective of this paper is to propose a model to develop control laws and energy management of a fuel cell system and of a fuel cell vehicle. Water phenomena into the device have a great influence on the stack efficiency and on faulty conditions. Henceforth the gas supply model must be able to work with a multi-species gas mix and to describe biphasic effects. To tackle the control objective, a formalism called Energetic Macroscopic Representation is presented and used. This paper presents an experimental validation of the proposed model.