Fuel cell based power sources start to be practically used in wide range and variety of applications. An example is application of fuel cell stack as the power source in electric vehicle drive. Paper includes description of construction design, testing and measurements results of hybrid fuel cell – supercapacitor system that was applied to supply Hy-IEL electric vehicle drive. Proton exchange membrane fuel cell (PEMFC) stack was used as main energy source because of its high power density, low operating temperature and quick response on load changes. There are many projects of fuel cell powered lightweight vehicles described in literature (Pios – hydrogen powered tricycle, HYSYRIDER – fuel cell based electric scooter, MHV – hydrogen vehicle and a few concepts of fuel cell powered electric bicycles). Typically batteries are applied as an energy buffer because a stand alone fuel cell system integrated into an electric drive is not always sufficient to provide the load demands of a vehicle. To provide peak power during transients such as start up, acceleration or sudden changes in load and also to take advantage of regenerative power of an electric vehicle at braking, much more suitable is application of a supercapacitor in addition to fuel cell. The primary purpose of using a supercapacitor instead of batteries as the energy buffer is the supercapacitor better power densities than conventional batteries and better energy densities than conventional capacitors. Performed research and measurements results have proved that supercapacitor can be interchangeably used to batteries for vehicular applications.