Battery-powered electronic resistance welding machine for sheet metal repair, comprising - a machine unit, which includes a handle, near which at least one activation and deactivation button is placed, - at least one first rod constrained in a sliding fashion and by means of a first elastic element to a terminal of said machine unit, said terminal being positioned on the opposite side with respect to said handle and said first rod having, at one free end opposite to said terminal, a ground electrode or tip that comes into contact with at least one metal portion to create an electrical circuit, wherein said metal portion is a welding resistance of said circuit, - at least one second rod, constrained in a sliding fashion and by means of a second elastic element to said terminal of said machine unit, said second rod having, at one free end opposite to said terminal, a welding electrode or tip for the fixing of repair accessories of said metal portion, - said first and second elastic elements being compression loaded and being adapted to counteract the sliding of said first and second rods (14, 17) towards the inside of the machine unit, characterized in that a rechargeable battery, for example a lithium-polymer accumulator, is placed inside said machine unit, said rechargeable battery being connected to a microprocessor electronic circuit, which is adapted to modulate a welding energy and power through an electronic control device; wherein said first and second rods (14, 17) are directly connected to said microprocessor electronic circuit, which is in turn directly connected to said electronic control device; and wherein, when said electronic control device is closed, and said ground and welding electrode or tip (16, 18) are in contact with said metal portion, the electrical current coming from said rechargeable battery flows through the control device only on said ground and welding electrode or tip (16, 18) of said first and second rods (14, 17) and on said metal portion through said terminal. - a machine unit, which includes a handle, near which at least one activation and deactivation button is placed, - at least one first rod constrained in a sliding fashion and by means of a first elastic element to a terminal of said machine unit, said terminal being positioned on the opposite side with respect to said handle and said first rod having, at one free end opposite to said terminal, a ground electrode or tip that comes into contact with at least one metal portion to create an electrical circuit, wherein said metal portion is a welding resistance of said circuit, - at least one second rod, constrained in a sliding fashion and by means of a second elastic element to said terminal of said machine unit, said second rod having, at one free end opposite to said terminal, a welding electrode or tip for the fixing of repair accessories of said metal portion, - said first and second elastic elements being compression loaded and being adapted to counteract the sliding of said first and second rods (14, 17) towards the inside of the machine unit, characterized in that a rechargeable battery, for example a lithium-polymer accumulator, is placed inside said machine unit, said rechargeable battery being connected to a microprocessor electronic circuit, which is adapted to modulate a welding energy and power through an electronic control device; wherein said first and second rods (14, 17) are directly connected to said microprocessor electronic circuit, which is in turn directly connected to said electronic control device; and wherein, when said electronic control device is closed, and said ground and welding electrode or tip (16, 18) are in contact with said metal portion, the electrical current coming from said rechargeable battery flows through the control device only on said ground and welding electrode or tip (16, 18) of said first and second rods (14, 17) and on said metal portion through said terminal.