Abstract: A fuel cell system having first and second fuel cells that each receive anode reactant flows and cathode reactant flows. Each of the fuel cells uses the reactant flows to produce electricity. The electricity production by the fuel cells produces respective first and second anode and cathode effluents that are exhausted from the respective fuel cells. The second fuel cell is connected to and downstream from the first fuel cell so that the anode reactant flow to the second fuel cell is formed from a portion of the anode effluent exhausted from the first fuel cell.

Abstract: A circuit configuration provides a simple device that can be used to monitor the voltage potential between any two points within the fuel cell coolant system without loading (i.e. decreasing) the voltage being monitored. The monitoring circuit include a lamp electrically coupled to the coolant system and arranged in a light-tight package with a photoresistor. When the ionization voltage for the lamp is reached, a fully isolated signal is provided in the form of an abrupt resistance change in the photoresistor. Visual and audible indicators can be coupled to the monitoring circuit to indicate a coolant contamination condition.

Abstract: A fuel cell system having first and second fuel cells that each receive anode reactant flows and cathode reactant flows. Each of the fuel cells uses the reactant flows to produce electricity. The electricity production by the fuel cells produces respective first and second anode and cathode effluents that are exhausted from the respective fuel cells. The second fuel cell is connected to and downstream from the first fuel cell so that the anode reactant flow to the second fuel cell is formed from a portion of the anode effluent exhausted from the first fuel cell.

Abstract: The present invention provides a simple device that can be used to monitor the voltage potential between any two points within the fuel cell coolant system without loading (i.e. decreasing) the voltage being monitored. The monitoring circuit include a lamp electrically coupled to the coolant system and arranged in a light-tight package with a photoresistor. When the ionization voltage for the lamp is reached, a fully isolated signal is provided in the form of an abrupt resistance change in the photoresistor. Visual and audible indicators can be coupled to the monitoring circuit to indicate a coolant contamination condition.