A circuit comprising: a power source; a power load; a storage device; a bidirectional DC to DC converter having a first operational mode and a second operational mode, said converter comprising: a first terminal pair that connects the converter to the power source and the power load, the first terminal pair including a positive terminal and a negative terminal, wherein the bidirectional DC to DC converter is connected in series with the power source and the power load via the first terminal pair; a second terminal pair that connects the converter to the storage device, the second terminal pair including a positive terminal and a negative terminal; an accumulation element for temporary accumulation of electric energy; and a switching circuit connected to the first terminal pair, the second terminal pair, and the accumulation element, wherein electric energy is transferred from the power source to the storage device via the accumulation element in the first operational mode; and electric energy is transferred from the storage device to the power load via the accumulation element in the second operational mode, wherein the switching circuit maintains a controlled voltage drop across the power load by selecting between the first operational mode and the second operational mode. a power source; a power load; a storage device; a bidirectional DC to DC converter having a first operational mode and a second operational mode, said converter comprising: a first terminal pair that connects the converter to the power source and the power load, the first terminal pair including a positive terminal and a negative terminal, wherein the bidirectional DC to DC converter is connected in series with the power source and the power load via the first terminal pair; a second terminal pair that connects the converter to the storage device, the second terminal pair including a positive terminal and a negative terminal; an accumulation element for temporary accumulation of electric energy; and a switching circuit connected to the first terminal pair, the second terminal pair, and the accumulation element, wherein electric energy is transferred from the power source to the storage device via the accumulation element in the first operational mode; and electric energy is transferred from the storage device to the power load via the accumulation element in the second operational mode, wherein the switching circuit maintains a controlled voltage drop across the power load by selecting between the first operational mode and the second operational mode. a first terminal pair that connects the converter to the power source and the power load, the first terminal pair including a positive terminal and a negative terminal, wherein the bidirectional DC to DC converter is connected in series with the power source and the power load via the first terminal pair; a second terminal pair that connects the converter to the storage device, the second terminal pair including a positive terminal and a negative terminal; an accumulation element for temporary accumulation of electric energy; and a switching circuit connected to the first terminal pair, the second terminal pair, and the accumulation element, wherein electric energy is transferred from the power source to the storage device via the accumulation element in the first operational mode; and electric energy is transferred from the storage device to the power load via the accumulation element in the second operational mode, wherein the switching circuit maintains a controlled voltage drop across the power load by selecting between the first operational mode and the second operational mode.