Abstract: A battery device has a housing adapted to be attached to a controller for operating a crane and to be powered by the battery device, a battery cell, and electronic circuitry connected to the battery cell and electrically connectable to the controller. A memory is provided in the electronic circuitry, wherein a function of the controller depends on the information in the memory. By providing a controller adapted to operate in one of a plurality of operating modes, wherein the operating modes comprise any of the following: an operation mode for controlling the operation of a crane, a simulation mode for communicating with a simulation device for simulating a crane, and a demonstration mode for demonstration of the different functions of the controller for controlling a crane, a controller for a crane is provided in which the selection of functions can be done in a controlled and defined way.