NOVELTY - A fuel cell system includes feedstock delivery system comprising water delivery assembly, carbon-containing feedstock delivery assembly, and reservoir. The feedstock delivery system regulates the flow of the streams in response to the detection of the triggering event by the sensor assembly to produce the feed stream containing a predetermined mix ratio of the liquid water and the liquid carbon-containing feedstock.    USE - For use in producing an electric current, used in motor vehicle such as recreational vehicle, automobile, or boat, dwelling such as house, apartment, duplex, office or store, or self-contained equipment such as microwave relay station, transmitting assembly, remote signaling or communication equipment.    ADVANTAGE - The inventive fuel cell system allows a batch of mixed feedstock components at predetermined mix ratio to be selectively dispensed to fuel processor while another bath of feedstock components at a predetermined ratio mix ratio is being prepared, thus increasing the ability of fuel cell system of fuel processing system to be able to meet an applied demand, and especially to do so while maintaining the predetermined mix ratio. The feedstock delivery system may include a controller without a user interface.    DETAILED DESCRIPTION - A fuel cell system comprises a fuel processor having a reforming region adapted to produce a stream comprising hydrogen gas as a majority component from a feed stream comprising water and a carbon-containing feedstock; a feedstock delivery system adapted to deliver the feed stream containing a predetermined mix ratio of feedstock components to the fuel processor; a sensor assembly associated with the reservoir and adapted to detect at least one triggering event related to the gravimetric quantity of one or more of the feedstock components in the reservoir; a fuel cell stack adapted to produce at least a portion of the stream containing hydrogen gas and to produce an electric current. The feedstock delivery system comprises a water delivery assembly adapted to provide a stream comprising liquid water; a carbon-containing feedstock delivery assembly adapted to provide a stream comprising a liquid carbon-containing feedstock; and a reservoir adapted to receive a volume of liquid water and a volume of liquid carbon-containing feedstock from the water and the carbon-containing feedstock delivery assemblies. The feedstock delivery system regulates the flow of the streams comprising the liquid water and the liquid carbon-containing feedstock at least partially in response to the detection of the at least one triggering event by the sensor assembly to produce the feed stream containing a predetermined mix ratio of the liquid water and the liquid carbon-containing feedstock.    An INDEPENDENT CLAIM is also included for a method for producing hydrogen gas for consumption by a fuel cell stack, comprising delivering a first liquid feedstock component to a mixing chamber until a sensor assembly detects a first triggering event, where the first liquid feedstock component comprises a first one of water or a carbon-containing feedstock; delivering a second liquid feedstock component to the mixing chamber until the sensor assembly detects a second triggering event, where the second liquid feedstock component comprises a second one of water or a carbon-containing feedstock, and further where at least one of the first and the second triggering events is related to the gravimetric quantity of at least one of the first and the second feedstock components delivered to the mixing chamber; withdrawing from the mixing chamber a liquid stream containing a predetermined mix ratio of the first and the second liquid feedstock components; delivering at least a portion of the liquid stream to a fuel processor having a reforming region and adapted to produce a stream containing hydrogen gas as a majority component; and delivering at least a portion of the stream containing hydrogen gas to a fuel cell stack adapted to produce an electric current.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of a feedstock delivery system in the invention.    Fuel processor (12)    Hydrogen stream (14)    Reservoirs (90', 90", 90"')    Sensor assembly (92, 114)    Sensor (93, 116)    Holding tank (112)