The smart grid is a new concept of electricity supply operation and management that will enable consumers and utilities to better control the electricity usage. This is possible because of the two way electricity and information communication between all nodes in the grid. For Electric Vehicles (EVs) travelling on the road, and because of the necessary battery charging times, there is a need for wireless communication between the EVs and the Electric Vehicle Supply Equipment (EVSEs) (charging stations) to discover the availability and make pre-reservations of charging time slots. In this paper, we introduce a new communication protocol between EVs and EVSEs that allows a reliable reservation process. The scheme, called Reliable Broadcast for EV Charging Assignment (REBECA) processes information about electricity usage in EVSEs and allows to reserve charging time slots for vehicles. REBECA also takes into account balancing energy usage between EVSEs while minimizing the latency time of EVs. Simulations results show the effectiveness of REBECA scheme.