A complete fuel cell system (10) is disclosed. The fuel cell system (10) comprises at least two fuel precursors (16, 18) that react to create hydrogen. A solid fuel precursor (18) can be carried in disposable fuel cartridges (100). A passive pressure control system including a dose pump (22) and a pressure equalization system (24, 300, 504) is provided to dose a liquid fuel precursor (16) to the solid fuel precursor (18) in the fuel cartridge (100). The solid fuel precursor (18) may include larger metallic particles coated by another fine metallic particles such that multiple micro galvanic cells are formed on the surface of the larger metallic particles. The fuel cell system (10) may also include a gas buffer (40) that stores produced hydrogen that is unneeded by the fuel cell, a water trapping mechanism (604) and an electronic vent (46) that consumes unneeded hydrogen.