A method includes assembling a top portion of a proton exchange membrane fuel cell based power generator that includes an anode cover, fuel cell, top portion of a valve assembly and fuel container cover. A bottom portion of the power generator that includes a fuel container with fuel, an opening for the top portion of the valve assembly, and a diaphragm portion of the valve assembly is also assembled. The top portion of the power generator is then attached to the bottom portion such that the bottom portion is a cathode of the power generator.