Patent ID: 7723954

Claim:
A method for supplying power to at least one load during failure of a main voltage source, wherein batteries serve as an emergency voltage source supply to the at least one load during failure of the main voltage source and are connected to the main voltage source, the method comprising: splitting the batteries into at least two battery groups, with the batteries of each group being connected in series; connecting each of the at least two battery groups in parallel to the main voltage source for charging, and connecting the at least two battery groups in series to the load for use as the emergency voltage source, wherein splitting the at least two battery groups and connecting the at least two battery groups in parallel to the main voltage source comprises using a single switching device, the single switching device comprising an element that is directly coupleable to each of the at least two battery groups such that the single switching device is configured to both split the batteries into the at least two battery groups and to connect each of the at least two battery groups in parallel, and wherein the at least two battery groups and the load are decoupled from the main voltage source by a diode device with at least one diode arrangement therebetween.