Abstract: The invention discloses a power unit (1) which comprises: an accumulator battery (2); an electric converter (3) supplied by said accumulator battery (2); an electric motor (30) supplied by said converter (3); a hydraulic pump (4) mechanically connected to said electric motor (30), suited to put under pressure a liquid (50) which supplies one or more actuators (9) in order to lift a load (11) connected to them. Said pump (4) is of the reversible type and operates as a hydraulic motor suited to drive into rotation said electric motor (30) which operates as a generator supplying said battery (2) by means of said converter (3) whenever the descent by gravity of the load (11) supported by said one or more actuators (9) puts under pressure the oil held therein which passes through said pump (4) entering from the delivery opening (42) and coming out of the inlet opening (41).