A dual mode DC-DC converter comprising: a first bridge converter having first and second switches ( S 1, S 2) connected in series, third and fourth switches ( S 3, S 4) connected in series, and the first and second series connected switches ( S 1, S 2) connected in parallel with the third and fourth series connected switches ( S 3, S 4); a second bridge converter having fifth and sixth switches ( S 5, S 6) connected in series, seventh switch and eighth switches ( S 7, S 8) connected in series, and the fifth and sixth series connected switches ( S 5, S 6) connected in parallel with the seventh and eighth series connected switches ( S 7, S 8); a transformer including a first winding having a first end (A') connected to a first node between the first and second series connected switches ( S 1, S 2) and a second end (B') connected to a second node between the third and fourth series connected switches ( S 3, S 4), the transformer further including a second winding having a first end (A") connected to a third node between the fifth and sixth series connected switches ( S 5, S 6) and a second end (B") connected to a fourth node between the seventh and eighth series connected switches ( S 7, S 8); an inductance in series with one of the windings (22, 24); and a controller, wherein the controller is operative in a first high-power mode whereupon all eight switches ( S 1 - S 8) are switched in a manner to transfer DC electrical power from the first bridge converter to the second bridge converter, or vice versa, characterised in that the controller is also operative in a second low-power mode whereupon the first, second, fifth, and sixth switches ( S 1, S 2, S 5, S 6) are switched in a manner to transfer DC electrical power from the first bridge converter to the second bridge converter, or vice versa, while the third and seventh switches ( S 4, S 7) are maintained in an off-state and the fourth and eighth switches ( S 4, S 8) are maintained in an on-state. a first bridge converter having first and second switches ( S 1, S 2) connected in series, third and fourth switches ( S 3, S 4) connected in series, and the first and second series connected switches ( S 1, S 2) connected in parallel with the third and fourth series connected switches ( S 3, S 4); a second bridge converter having fifth and sixth switches ( S 5, S 6) connected in series, seventh switch and eighth switches ( S 7, S 8) connected in series, and the fifth and sixth series connected switches ( S 5, S 6) connected in parallel with the seventh and eighth series connected switches ( S 7, S 8); a transformer including a first winding having a first end (A') connected to a first node between the first and second series connected switches ( S 1, S 2) and a second end (B') connected to a second node between the third and fourth series connected switches ( S 3, S 4), the transformer further including a second winding having a first end (A") connected to a third node between the fifth and sixth series connected switches ( S 5, S 6) and a second end (B") connected to a fourth node between the seventh and eighth series connected switches ( S 7, S 8); an inductance in series with one of the windings (22, 24); and a controller, wherein the controller is operative in a first high-power mode whereupon all eight switches ( S 1 - S 8) are switched in a manner to transfer DC electrical power from the first bridge converter to the second bridge converter, or vice versa, characterised in that the controller is also operative in a second low-power mode whereupon the first, second, fifth, and sixth switches ( S 1, S 2, S 5, S 6) are switched in a manner to transfer DC electrical power from the first bridge converter to the second bridge converter, or vice versa, while the third and seventh switches ( S 4, S 7) are maintained in an off-state and the fourth and eighth switches ( S 4, S 8) are maintained in an on-state.