Patent attributes
A complex impedance battery monitor has one or more primary switches, a load resistor in series with the primary switches, a current sensor in series with the primary switches, two or more lead wires connected to two or more busbars in a string of batteries, and a digital signal processor. The primary switches are connected to two or more terminals of the batteries in the string of batteries. The primary switches are turned on and off to produce a ripple current in the string of batteries. The digital signal processor determines at least a portion of the complex impedance of at least one of the batteries by analyzing the voltage and current waveform of the ripple current. The primary switches may be turned on and off with a pulse width modulated wave.
