a fuel cell assembly includes a manifold having a plurality of fuel cell connecting zones . at least some of the zones have differing characteristics such as area and arrangement of electrical connections and inlet and outlet ports corresponding to differing electrical power capacities . the assembly also includes one or more fuel cell stacks . at least some of the stacks have differing electrical power capacities , differing characteristics corresponding to the differing characteristics of the manifold zone , and corresponding differing arrangements of electrical connections and inlet and outlet ports . these differing characteristics are designed so that a fuel cell stack of a particular capacity can be connected only to a manifold zone corresponding to such capacity .