The performance of a asymmetric (single-side) pasted positive plate was studied by measuring the current density and potential distributions on both sides of the plate. It was found that the current densities on both sides are almost the same during the early discharge at the 3 C discharge rate. As the discharge proceeds, the current decreases gradually on the non-pasted side and increases on the pasted side. Since more active mass exists on the pasted side, the matrix resistance is higher, causing the polarization to increase by 55-90 mV at the 3 C discharge rate. On the non-pasted side, the active mass undergoes a deeper depth of discharge (DOD). This leads to the shedding of active mass, which shortens the battery life. Since the positive grid on the non-pasted side is exposed, its corrosion rate is faster.