Method & apparatus to ensure that saturation of the battery does not occur during resonant finding phase as well as implementation methods to quickly find resonance

One embodiment of the present invention provides that saturation will not be not reached by initially probing the battery and taking data on the current as the probe frequency is swept. At or near resonance the current will begin to increase. At this point the signal generator reduces the current to a present level (a limit) and keeps track of the current CHANGE. This process is repeated as the signal is swept and at resonance the CHANGE will be maximum (when compared to the average). In other words, the first signal NOT at resonance is kept as the ceiling and any change is noted against this ceiling. The second derivative of the change can show the minima which when plotted versus frequency will yield the correct resonance.