This thesis presents a part of the BAT-MAN research/industrial project conducted by Brain Technologies s.r.l. The project is a collaborative effort, including the contributions of Brain Technologies, S.I.V.E s.p.a, and Politecnico di Torino. The ultimate objective of this project is to develop and produce a battery management device capable of both the estimation and prediction of Lead-Acid battery working parameters, in real-time. The scope of this thesis is on the mathematical algorithm used to compute the parameters in question, namely the State of Charge (SoC) and State of Health (SoH). This algorithm stands out amongst others available in literature as it is a variable-SoH algorithm, whereas others rely on a fixed SoH (usually that of a new battery, i.e.