The paper presents a set of experimental investigations related to the study of the dynamic behavior of supercapacitors. The experimentally-inferred results are then used as inputs for an improved version of one of the most common supercapacitor RC-circuit models. The key improvement concerns the accurate modeling of the redistribution phenomenon of the supercapacitor residual charge during charging/discharging and relaxation phases. The accuracy of the obtained model has been experimentally validated. Preliminary physical investigations concerning the temperature effects on the SC dynamic behavior are also presented and discussed.