In this thesis it will be shown the usage and the exploitation of a battery sensor, already used by Iveco onboard of the vehicles, with a diagnosis purpose. The strength of this approach is the possibility to take advantage of something already present onboard of the vehicle, but also the possibility to have an historical trend of the measurement and of the states of the battery. In addition, the standard among the dealers of truck makers offers often wrong measurements leading to a wrong replacement of the batteries, so a change in the method of the diagnosis is required. The proposed method consists in the usage of an Intelligent Battery Sensor (IBS) that continuously estimates SOC, SOH and the internal resistance value, and measures the temperature, the voltages and the battery current.