Inclusion of an appropriate form of carbon as an additive in the negative active material (NAM) improves the performance of lead–acid batteries in high rate partial state of charge (HRPSoC) cycling. We have used cyclic voltammetry to evaluate the performance of different carbons – carbon black, acetylene black and graphite – in this study and found the technique to be useful in separating the capacitive and the Faradaic contributions to the total charge. It is noted that the presence of carbon at the Pb-interface substantially enhances the electrochemical activity and increases the Faradaic charge, while high surface area carbons add to the capacitive charge. The technique is further used to study combinations of carbons as physical mixtures and bilayers.