An invention is provided for detecting polarization in a battery during battery charging. The invention includes applying a waveform to a battery, and obtaining a plurality of battery response voltage readings corresponding to points along the applied waveform. A battery response voltage curve is calculated based on the voltage differences between the plurality of battery response voltage readings. A battery polarization point is then identified when the slope of the battery response voltage curve stops increasing at an increasing rate. To enhance accuracy, a plurality of battery response voltage curves can be calculated, each based on voltage differences between battery response voltage readings taken along the waveform. The battery polarization point can then be identified when the slopes of all the battery response voltage curves stop increasing at an increasing rate.