Patent ID: 6583603
Filing Date: 2003-06-24
Classification: G01R,H02J

Abstract:
An apparatus for selectively charging and testing battery cells in one or more strings of battery cells electrically connected to one another within each string and employed as a back-up power supply for a primary power source, the one or more strings of battery cells selectively connectable to a load bus supplied by the primary power source in order to deliver power in the event of a failure of the primary power source, the apparatus comprising:a main control module having a first power supply for supplying a charging power bus and a discharge bus; and one or more battery string modules each connected to a respective string of battery cells of the one or more strings of battery cells and to the load bus and configured to selectively electrically isolate the respective string of battery cells from the load bus, each of the one or more battery string modules having: a regulator configured to receive charging power from the first power supply via the charging power bus, and supply and regulate charging power to the respective string of battery cells; a controllable impedance; a first controllable switch electrically connected in parallel with the controllable impedance, wherein the parallel combination of the controllable impedance and the first controllable switch is connected in series between the load bus and the corresponding string of battery cells; and a first controller configured to selectively control the controllable impedance and the first controllable switch, wherein the first controller detects when a voltage of the load bus is falling and subsequently initiates operation of the controllable impedance and the first controllable switch simultaneously, wherein the controllable impedance is operated for a predetermined time period.