This paper extends previous work on the use of maximum length sequences as tools for parameter estimation within electrochemical batteries. An improved technique using a simplified monopolar current pulse excitation strategy allows identification of Randles’ model equivalent circuit values, which can be subsequently employed in state-of-charge and state-of-health algorithms. Within the approach the problems associated with establishing bulk capacitance over a short time period are avoided. Instead, using readily identifiable parameters (surface capacitance, series resistance and charge transfer resistance) comparison of parameters for new and aged batteries is carried out, and a potential indicator for State of Health described. Experimental results are presented to verify the proposed technique.