Energy supply unit and method for determining absorbed electrical energy

The unit has an electrical energy storage unit (20) i.e. accumulator, for storing electrical power. An electrical connection unit connects an external voltage source with a charging station. A branch circuit supplies the electrical power to an electric drive (14) of a motor car (10). Another branch circuit supplies electrical power to a heating and/or air conditioning unit (32) of the motor car. A power detecting unit separately detects the electrical power consumed by the electric drive and the electrical power consumed by the heating and/or air conditioning unit. The energy storage unit serves as a direct current (DC) power source. Independent claims are also included for the following: (1) a motor vehicle powertrain (2) a method for determining electrical power consumed by a power supply unit.