Maintenance-free battery

In a maintenance-free lead-acid battery comprising a battery container having a plurality of cells, a cover sealed to the container, venting means providing passages for the escape of evolved gas and an electrolyte contained in the cells, each cell having components including a plurality of positive and negative electrodes disposed therein comprising a grid supporting structure having a layer of active material attached thereto, the improvement wherein the grid supporting structure of the positive electrodes are formed from a ternary lead base alloy consisting essentially of lead, from about 1.0 to about 2.0% antimony and from about 1.2 to about 2.2% cadmium, the cadmium being present in an amount at least equal to the amount of antimony present, and the grid supporting structure of the negative electrodes are formed from a ternary lead base alloy consisting essentially of lead, from about 0.06 to about 0.20% calcium and from about 0.10 to about 0.40% tin, the percentages of each alloy being based on the alloy weight.