25 hours The battery in theory can supply 32 Amp hours. So divide that rating by the actual draw to get your results 32 Ah / 1.28 A = 25 h So the battery can theoretically supply 1.28 amperes continuously for 25 hours. But in reality, the Ah rating of a battery is usually dependent upon the current draw. A lower current draw will generally result in a higher effective Ah rating than a higher current draw.