An electric vehicle includes a drive system which operates a method of transferring power between the vehicle and an external power grid. The drive system includes a battery, a rectifier, and a processor. The processor is configured to connect the rectifier between an alternating current (AC) port of an outlet of an external power grid and the battery, the rectifier configured to convert between an AC power at the AC port on a grid side of the rectifier and a direct current (DC) power at a vehicle side of the rectifier in order to transfer power bi-directionally between the external power grid and the battery.