Daimler Chrysler Ag

Hans-Peter Sch&ouml;ner

Alf Blessing

Process for monitoring the residual charge and the capacity of a battery, where at least two voltage-current measurements have been carried out on the load-carrying battery. The current load of the battery selected here should be greater than 30% of the nominal capacity per hour, e.g. for a 100 Ah battery, at least 30 amperes. The initial voltage-current measurement is taken at an initial time for an initial load condition of the battery. A second voltage-current measurement is carried out at a second time for a second load condition of the battery. It is essential here that the load condition of the battery has changed because of the current that has been drawn. The current-voltage measurements produce an initial measuring point and a second measuring point. The two measuring points set an interpolation line and determine the point of intersection with a limiting voltage level (U,). This point of intersection is marked by a so-called limiting current (I,). The limiting voltage level is decided from the minimum voltage required by the connected consumers in order for them to operate fault-free. The limiting voltage level is therefore stipulated for the technical layout of the battery system and is known. Furthermore, fault-free operation of the connected consumers requires a minimum operating current (I,), which is also specified and known as a design parameter of the battery system. The difference between the determined limiting current I,and the minimum operating current I,is determined and recorded. This difference is a dimension for the residual charge of the battery that is still available and in accordance with the invention is here designated as the limiting current reserve.

Growing community of inventors

Modautal, Germany

Hans-Peter Schöner

Growing community of inventors

Modautal, Germany

Hans-Peter Sch&ouml;ner

Hans-Peter Schöner