The outdoor I‐V curve of a concentrating photovoltaic (CPV) Multi‐junction (MJ) module is affected by temperature, series resistance, electro‐optical mismatches among receivers mainly due to soiling effects, tracker misalignment and a particular spectral solar content. Starting from the previous works [1] and [2] and considering CPV MJ modules of only‐one string with series‐connected receivers, an original algorithm is developed to identify the photovoltaic current and the operating junction temperature of each receiver. Power losses due to the temperature, the series resistance and the electro‐optical mismatches can be separately identified as well.