Patent ID: 8239149

Claim:
A method for determining the operating condition of a solar panel, wherein the solar panel is controlled by an electronic module, comprising the steps of: measuring a temperature of the solar panel; determining the instant maximum power condition of the solar panel; selecting a condition of voltage and a condition of current that correspond to the instant maximum power point condition; controlling the solar panel to provide the selected condition of voltage and condition of current; comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel; and if the instant maximum power condition varies from the model by more than a predetermined value, taking the additional steps of: determining the instant series resistance of the solar panel; determining the instant shunt resistance of the solar panel; and determining the cause of the variance from the model according to a rule, wherein the rule determines that a solar panel is shaded if the solar panel is not damaged and further that power production of the solar panel is dissimilar to other nearby solar panels in a solar panel system.