In this paper the problem of assigning electric cars to charging stations in a distributed manner is addressed, resorting to Lagrangian-based distributed algorithms. Within such algorithms, the routing process is the result of a cooperation among several decision makers, having each one a local knowledge of the system. The decision makers are in charge to decide the type of information to be exchanged. Our focus is to investigate the performance of different algorithms based on different knowledge degrees of the system. The implementation issues and the effectiveness of the algorithms are analysed via simulation. The trade-off between knowledge degree and system performance is currently under study.