to the control unit and can hence be connected directly to for example the battery modules as well or to other control means of a vehicle the memory unit 114 is configured to store for example battery parameter status measured by the measuring unit 110 adjusted charge current provided from the generator 108 to the battery modules 102 104 106 etc hereby for a given state of the battery modules 102 104 106 the memory unit stores the charge current provided by the generator 108 accordingly the memory unit 114 which in one example embodiment is a pid regulator receives and stores more or less all possible information regarding the state of the battery modules 02 104 106 as well as commands given by control unit 112 for such battery module information reference is now made to fig2 and 3 which illustrate two example embodiments of the method according to the present invention firstly fig2 illustrates an example where two of the above described battery modules 102 104 have been recently replaced with new unused battery modules hence the third battery module 06 is older than the newly exchanged first 102 and second 104 battery modules secondly fig3 illustrates an example where the third battery module 106.