TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The first and second hydrogen-storing materials are different from one another. The first hydrogen-storing material comprises a metal hydride or a material comprising reversible metal hydrides, zeolites or carbon-based hydrogen-storing materials. The apparatus comprises: a continuous thermally-conductive path extending between the first and second hydrogen-storing materials, where the continuous thermally-conductive path is configured to allow heat to flow from the first hydrogen-storing material to the second hydrogen-storing material while hydrogen flows from the satellite cartridge into the hydrogen reservoir; a heater disposed to heat the second hydrogen-storing material; an electrical current source connected to the second hydrogen-storing material, where the electrical current source is configured to heat the second hydrogen-storing material by passing an electrical current through the second hydrogen-storing material; a pressure regulator disposed in a fluid path between the hydrogen reservoir and the fuel cell, where the pressure regulator is configured to provide hydrogen to the fuel cell at a pressure that is lower than a pressure within the hydrogen reservoir; and a closure mechanism that when opened is configured to allow the fluid communication of the satellite refueling cartridge with the hydrogen reservoir. The first and second hydrogen-storing materials are at equal temperatures. The plateau pressure of the second hydrogen-storing material is lower than the charging pressure of the first hydrogen storing material. The heater is an electrical heater configured to be energized when the fluid coupling between the satellite refueling cartridge and the hydrogen reservoir is established. The fuel cell is configured to receive hydrogen at a pressure equal to a pressure in the hydrogen reservoir. The portable device comprises a fuel cell layer in fluid communication with the hydrogen reservoir, where the fuel cell layer includes the fuel cell. The satellite refueling cartridge is in fluid communication with the hydrogen reservoir via a detachable fluid coupling comprising a magnetic coupling, threaded couplings, bayonet couplings or adhesive couplings.