Due to their flexible power response, electrochemical Battery Storage Systems (BSS, or SdA in Italian) have gained attention as possible providers of Auxiliary Services (AS). BSS in Electric Vehicles (EVs), in particular, could provide AS while the EV is charging. This article investigates how profitable the Balancing Service (SB) could be for the EV owner: an optimization problem is formulated to determine the energy to offer on the Italian Balancing Market (MB) to minimize the cost of recharging the desired amount of energy; the offer prices for the service and the acceptance/rejection status of the offers are assumed as known input values; hourly and quarterly offers are considered. The simulated case studies relate to night-time charging and concern two types of end user, with different values of maximum charging power, energy to be recharged and taxation on energy exchanges in the bill; both unidirectional (V1G) and bidirectional (V2G) charging are analyzed. Overall annual results show that, if there is a small amount of energy to be recharged, moderate savings can be achieved in the bill compared to not providing the SB; Significant savings can be achieved if there is a greater amount of energy to be recharged (as in the case with non-domestic users) and V2G charging is adopted, so that the sale of energy is emphasized for the upward SB.