If Iron Man's Tony Stark lived in the Victorian period he might have looked something like this:
Original image from Cassell's Family Magazine, 1886, page 576
The light source was powered by a similar sized battery, just to add to that likeness. Accompanying text:
'A very neat portable hand electric lamp has been introduced for use in mines, gunpowder works, and other inflammable places, besides being adapted for use as a railway or carriage reading-lamp ... the box, B which is of varnished teak, and has a flat, flexible leather handle ... The size of the box is 6 by 5 by 4 inches, and the weight of the whole is only 6lbs ... can be put under the seat of the carriage, or in the hat-racks, while the lamp is held in the hand, or fixed to the button-hole of the coat.'
The rest of the text discusses the chemistry behind the batteries suitable for such a device which I won't go into.
Robert Downey Jnr as Mr Stark wired up to a car battery: