Discrete frequency immittance spectroscopy (DFISTM)-a new technique for battery instrumentation

We describe a new technique for accurately determining a lead-acid battery´s performance without actually discharging it. The battery is excited with periodic currents and its complex impedance (or admittance) is determined at n discrete frequencies. By mathematically combining the 2n measured quantities, the elements of a 2n-element equivalent circuit model of the battery are evaluated. The electrical elements represent actual physical and/or electrochemical processes occurring within the battery and their values yield previously unavailable information concerning the battery´s performance