Low-cost wood sawdust was investigated as a primary source for preparing active carbon to enhance the leadacid battery. This can give a scope to determine the suitable active functional groups required to develop that battery. The fraction, − 1.0 mm in size, was a potential feedstock for the active carbon preparation using phosphoric acid activation. The resulting precursor/H3PO4 mixture was pre-activated by solidifying at 150 ◦C for 2 h to eliminate water, leaving it a black adhesive solid. The hardened mixture was heated at 450 ◦C for an hour at a rate of 10 ◦C min− 1 to complete the carbonization process. The produced active carbon was washed repeatedly with deionized water, dried at 105 ◦C, and saved in plastic for analysis and use, it was called (oxidAC). The resulting active carbon has been identifed using different analytical methods such as; XRD, SEM, FTIR, and BET. Results obtained revealed that the activated carbon additive, with a 2.5 % weight percentage, can reduce effectively the accumulation of PbSO4 at the positive active material (PAM) of the lead-acid battery. The role of the active carbon in improving the PAM behavior can be explained based on lead (II) ion adsorption on the carbon surface.