After watching a video on using Fuel Cells to power an electric car, I came up with a wild idea to have an Hydrogen on Demand electrolysis cell with a Fuel Cell to provide power for and electric car. the oxygen would also be provided by the HOD system with a slight modification to the cell separating the Hydrogen and Oxygen outputs. The output of the Fuel Cell would be water and electrical power so all one would have to do is fill the car's modified fuel tank up with water and go. The water output of the fuel cell would be routed back into the fuel tank. The only water loss would possibly be vaporization of water due to heat. Since fuel tanks on modern cars have a vent, that vent would have to be replaced with something that would keep the water vapor in and let the air pressure out.