Lighting device with control of power flow direction

A method for controlling operation of a lighting device having a light source configured to be driven by electrical power, a power interface for energy transfer with an external electrically driven device that can be connected to the power interface, an energy-storage unit configured to receive electrical power via the power interface, to store received electrical power as electrical energy, and to deliver stored electrical energy to the light source as the electrical power and to the power interface, and to allow, when the external electrically driven device is connected to the power interface such that the power interface is in a connected state, an energy-transfer operation between the energy-storage unit and an external second energy-storage unit of the external electrically driven device in a controllable energy-transfer direction via the power interface, the method comprising:

• determining if the power interface is in the connected state;
• determining a current light-output state of the lighting device;
• wherein the current light-output state of the lighting device is an operational state of the light source of the lighting device;
• and
• controlling, in the connected state, the energy-transfer operation in an energy-transfer direction depending on the current light-output state of the lighting device.