A dynamic battery array of .[.individual.]. .Iadd.discrete .Iaddend.cells, controllably interconnected for instantaneous dynamic configuration into a plurality of individual power buses having different electrical power output characteristics, each of which is tailored to supply the electrical power required at the instant by a particular electrical load within a circuit. Preferably the cells are fungible and randomly available so that at any given instant any given cell can be poweringly associated with a particular electrical load. The dynamic battery array, consisting of discrete cells lends itself to mounting on physically flexible substrates such as credit cards. The programmable array employs low resistance switch arrays for dynamically and instantaneously forming individual power networks or power buses between selected power cells and individual electrical loads in electrical circuits. The circuits to which such battery arrays are applied are generally complex circuits in which several different loads occur, each of which has a different power requirement.