Abstract: A reverse current protection device includes one or more contactors in a power circuit that open to prevent current flow and close to allow current flow; an impedance buffer to invert voltage across the diode; a threshold detector to compare inverted voltage to a reference voltage to determine a good or fault diode condition; an opto-isolator actuatable by the threshold detector when at least one of a good diode condition is determined and a fault diode condition is determined; and a relay in communication with the opto-isolator to cause at least one of the one or more contantors to close in a good diode condition and open in a fault diode condition.

Abstract: An active voltage limiting and failure detection system for an energy storage cell of a multiple energy storage cell pack includes a first electrical circuit and a second electrical circuit connected to the energy storage cell. The first electrical circuit is powered by the energy storage cell and includes means for drawing a significant amount of power from the energy storage cell when a cell voltage Vcell reaches a maximum voltage Vmax to reduce the cell voltage Vcell, means for stopping the drawing of the significant amount of power to reduce the cell voltage Vcell when the cell voltage Vcell reaches a minimum voltage Vmin, and means for drawing no power when the cell voltage Vcell reaches a shutdown voltage Vshutdown. The second electrical circuit includes means for indicating a cell active condition when the cell voltage Vcell is above a threshold active voltage Vactive, and means for indicating a cell inactive condition when the cell voltage Vcell drops below the threshold active voltage Vactive.

Abstract: A reverse current protection device for a fuel cell of a power circuit protects the fuel cell from damage caused by reverse current into the fuel cell caused by a faulty diode. The reverse current protection device includes a contactor for opening the power circuit to prevent current from flowing therethrough and for closing the power circuit to allow current to flow therethrough, means for measuring the voltage across the diode to determine if the diode is in a good condition or a fault condition, means for causing the contactor to be closed if the diode is in a good condition and open if the diode is in a fault condition so that current does not flow through the contactor, protecting the fuel cell from damage caused by reverse current through the diode and into the fuel cell.

Abstract: An active voltage limiting and failure detection system for an energy storage cell of a multiple energy storage cell pack includes a first electrical circuit and a second electrical circuit connected to the energy storage cell. The first electrical circuit is powered by the energy storage cell and includes means for drawing a significant amount of power from the energy storage cell when a cell voltage Vcell reaches a maximum voltage Vmax to reduce the cell voltage Vcell, means for stopping the drawing of the significant amount of power to reduce the cell voltage Vcell when the cell voltage Vcell reaches a minimum voltage Vmin, and means for drawing no power when the cell voltage Vcell reaches a shutdown voltage Vshutdown. The second electrical circuit includes means for indicating a cell active condition when the cell voltage Vcell is above a threshhold active voltage Vactive, and means for indicating a cell inactive condition when the cell voltage Vcell drops below the threshhold active voltage Vactive.