Authentication system for a plug-in electric drive vehicle

An energy auditing system for a plug-in electric drive vehicle, the system comprising:

• a first device electrically connectable to a first power apparatus;
• an electrical power connector to establish an electrical power path between the first device and a remote device which is electrically connectable to a second power apparatus;
• the first device comprising:
• control means to control operation of the first device;
• a first sensor to selectively measure an amount of electrical energy delivered to or received from the first power apparatus and to generate a first signal representative of the measured amount;
• a control switch configurable to electrically connect and disconnect the first device to the first power apparatus;
• and
• a receiver configured to receive an energy audit signal transmitted from a remote device, the energy audit signal representative of an amount of energy transferred over the electrical power path in a specified time interval;
• wherein the first device's control means is operable to compare the first signal with the received energy audit signal in the same specified time interval and to electrically disconnect the first device from the first power apparatus when a power loss between the respective devices is detected.