This academic work is part of the BAT-MAN research and development industrial project owned by brain Technologies, sponsored by the regional contribution POR FESR 2014-2020 (European fund for the regional development) and whose main goal is the realisation of an electronic device capable of detecting and forecasting, in real-time, the working conditions of a Lead-Acid battery. Entering the team as Algorithm and Control Engineer, I’ve been in charge of analysing the problem, defining experimental campaigns and creating the algorithm for the real-time batteries’ states estimation. The work can be divided into three major sections: 1)Energetic Framework definition 2) Battery modelling 3) Model-based Solution The definition of a rigorous Energetic Framework, that mathematically describes the main quantities necessary to define the state of a battery (SoC, SoH, etc.) and the energy exchanges, was the first solid milestone on which building all the reasoning.