Method for determining the absolute point of maximum power delivered by a string of photovoltaic panels connected together in series, said method foreseeing to cyclically perform, for every time interval ΔT 1 of predetermined value, the following operations: - starting from the voltage value V i set for said string of photovoltaic panels, increasing and reducing said voltage value V i by a predetermined voltage quantity ΔV 1; - observing the variations of the power P Vi + ΔV1 and P Vi - ΔV1 delivered by said string at said voltage values V i + ΔV 1 and V i - ΔV 1, respectively, with respect to the value of the power P Vi delivered at said set voltage value V i; - in the case in which one of said power values P Vi + ΔV1 or P Vi - ΔV1 is greater than said power value P Vi, setting as voltage value V i on said string of photovoltaic panels said voltage value V i respectively increased or decreased by said voltage quantity ΔV 1; said method being characterised in that it foresees, for every time interval ΔT 2, > ΔT 1, that the following sequence of operations be carried out, repeating it a maximum number of times M, said sequence of operations foreseeing to: - decreasing said voltage value V i set for said string by a voltage quantity equal to ΔV 2, wherein ΔV 2 is selected substantially equal to the nominal open circuit voltage value of each of said photovoltaic panels belonging to said string; - observing the value of said power P Vi - ΔV2 delivered at said voltage value V i - ΔV 2; - in the case in which said power value P Vi - ΔV2 is greater than the value of the power P Vi delivered at the set voltage value V i, setting as voltage value V i on said string of photovoltaic panels said voltage value V i decreased by said quantity ΔV 2, or in the opposite case interrupting the repetition of said sequence of operations. - starting from the voltage value V i set for said string of photovoltaic panels, increasing and reducing said voltage value V i by a predetermined voltage quantity ΔV 1; - observing the variations of the power P Vi + ΔV1 and P Vi - ΔV1 delivered by said string at said voltage values V i + ΔV 1 and V i - ΔV 1, respectively, with respect to the value of the power P Vi delivered at said set voltage value V i; - in the case in which one of said power values P Vi + ΔV1 or P Vi - ΔV1 is greater than said power value P Vi, setting as voltage value V i on said string of photovoltaic panels said voltage value V i respectively increased or decreased by said voltage quantity ΔV 1; said method being characterised in that it foresees, for every time interval ΔT 2, > ΔT 1, that the following sequence of operations be carried out, repeating it a maximum number of times M, said sequence of operations foreseeing to: - decreasing said voltage value V i set for said string by a voltage quantity equal to ΔV 2, wherein ΔV 2 is selected substantially equal to the nominal open circuit voltage value of each of said photovoltaic panels belonging to said string; - observing the value of said power P Vi - ΔV2 delivered at said voltage value V i - ΔV 2; - in the case in which said power value P Vi - ΔV2 is greater than the value of the power P Vi delivered at the set voltage value V i, setting as voltage value V i on said string of photovoltaic panels said voltage value V i decreased by said quantity ΔV 2, or in the opposite case interrupting the repetition of said sequence of operations.