Nowadays, it is increasingly common to hear about environmental issues. This fact keep us to continually try to improve energy optimization, either through new storage devices that pollute less or improvements in the environmental energy generation systems. Recent new types of devices under study are those called supercapacitors. Supercapacitors are electronic devices able to store charge in form of electrical energy. This energy is stored as an electric field, so supercapacitors are less polluting than standard batteries, which obtained its energy by chemical reactions. Their name is determinate by the high capacity that can achieve (up to 1000 F). The aim of this project is to find a model to characterize the behaviour of supercapacitors from their charge and discharge, analyze the efficiency of these devices and try to find if the energy losses could be represented only by a series resistance or not. The steps that have been followed to achieve the main aim were to design a charge-discharge circuit based on two methods (constant current source and pulse current source); collect and process the measurements obtained and analyze the supercapacitors behaviour during the process of charge-discharge. Finally, a model of an equivalent circuit for supercapacitors have been found and characterize whit the values obtained from the results of charge-discharge process. In order to validate the model searched, it has been simulated with a simulation program.