TECNALIA has become a key active player in technology development for electric vehicles (EVs), in the fields of materials, mechanics, power electronics and smartgrids. In order to contribute to the development of the technologies dealing with the new paradigm that integrates EV within the grid, where large EV fleets are connected to the grid and can even take part in the electricity markets, TECNALIA has deepen into the definition of the information needed in order to define the charging sequence of EVs. This paper explains the characterization of those elements, related to the vehicle and the user, which could influence on the definition of the optimal charging sequence of EVs. Modelling the behaviour of the vehicle charging system leads to the possibility of establishing charging sequences that minimize the energy spent per charging cycle. This information has been included in a communication protocol developed by TECNALIA and implemented in the EV-ON platform, which purpose is the development of smart charging and Vehicle to Grid (V2G) algorithms.