During high-rate discharge, there is less utilization of the sealed, valve-regulated lead/acid VRSLA batteries because the secondary current distribution is less uniform and there is less time for ion diffusion. This study investigated the effects of positive plates' material porosity, positive/negative active material ratio, and electrode stacking pressure on cell performance during high-rate discharge. According to the experimental results, the cells with a porosity of 74–76% and positive/negative active material ratio of 1.2–1.5 exhibited the best cell performance. Cells with higher electrode stacking pressure exhibited higher initial capacity and average capacity per cycle with lower capacity loss per cycle.