an electrically powered vehicle achieves maximum structural strength with minimum weight by utilizing a combined body and chassis formed entirely of plastic material , molded and bonded into an integral composite structure which includes a central , hollow longitudinal beam , top , bottom , and side panels of the vehicle body portion , and a power unit supporting chamber at the forward end closing the forward end of the beam and tying it to the side panels . the beam holds the batteries , and the chamber contains all of the components of the power unit including the controlling device . the structure is thus as rigid and light as possible , in addition to eliminating any possibility of any unwanted grounding or electrical paths . the only metal in the vehicle is that of the additional components such as road wheels , suspension members , steering , and power unit and the fasteners and brackets used to retain them in mounted position .