preferably between 0 1 and 30 seconds the soh value obtained in this manner is a function of soc and u03b4v i e soh f soc u03b4v the result indicates the state of health of the battery allowing the determination of whether it is in a condition to start the engine with particular but not exclusive reference to the presence of a stop and start device in the vehicle the two parameters soc and u03b4v also consequently like the parameter soh are a function of the temperature the values which are determined through such measurements must therefore be fixed in relation to the temperature noted at the time of the measurements using the soc and u03b4v data the initial value of soh is defined through the cartesian plane of fig2 which illustrates the subdivision of the areas that differentiate the conditions of a battery in a dynamic situation first of all two quantities are fixed that define the limits within which engine start up is guaranteed in particular a soc min is established below which engine start up is not guaranteed and a u03b4v max above which engine start up is not guaranteed at this point the value of u03b4v that is recorded following the application of the load is normalized within the area.