A method for determining the ability of a vehicle to start, in order to detect the operational capability of a battery, in particular of a vehicle battery, in a particularly simple and reliable way. Current values and voltage values of the battery are sensed during a predefined time window, in particular while the vehicle is being started. An internal resistance of the battery is determined by reference to the current values and the voltage values by means of linear regression, and a reference resistance value for the starting behavior of the vehicle is determined by reference to a maximum value for the current and a minimum value for the voltage which are sensed within the predefined time window. A value which represents the ability to start is determined by reference to a comparison between the internal resistance and the reference resistance value.