A method and arrangement of determining starting conditions of a solar converter in a photovoltaic system. The photovoltaic system includes a photovoltaic panel system having one or more photovoltaic panels. The method includes determining an open circuit voltage of the photovoltaic panel system, and determining beforehand limit values for the starting conditions, where the limit values include an open circuit voltage value and a temperature value, with which values the solar converter can be started. The method also includes determining beforehand the temperature dependency of the open circuit voltage of the panel system, determining a temperature of the panel system, and setting a criterion for starting the converter. The criterion includes determining, by using the determined temperature dependency and the determined limit values for the starting conditions, whether the determined temperature and the determined open circuit voltage enable the starting of the converter.