The battery of an electrical vehicle (EV) can be used to support the power grid (V2G, Vehicle-to-Grid) or can act as a buffer for a home promoting self-consumption (V2H, Vehicle-to-Home). This technical report evaluates, in laboratory conditions and for different charging/discharging power levels, the round-trip efficiency of an EV and V2G/V2H charger setup. The round-trip efficiency of the setup was determined to be ca. 80% for the studied charging/discharging power levels. The tests were performed in the Smart Grid Interoperability Laboratory, located in the Joint Research Centre (JRC) site in Petten, Netherlands.