A battery including: a casing having a cylindrical portion, an end portion configured for covering an opening disposed in an end of the cylindrical portion, and an inner surface defining a chamber in which an electrolyte is disposed therein; a conductive surface located within the chamber adjacent the inner surface of the casing, the conductive surface being configured for electrical communication with an anode terminal of the battery; a permeable separator sheet located within the casing configured for electrically isolating the electrolyte from the conductive surface; a conductive rod having a first end configured for electrical communication with a cathode terminal of the battery, and, a second end of the conductive rod configured for electrical communication with the electrolyte; wherein the end portion and the cylindrical portion are movably attached to each other, the end portion and cylindrical portion being movable relative to each other between at least a first attached position whereby the end portion covers the opening disposed at the end of the cylindrical portion so as to substantially block ingress of a liquid into the casing via the opening, and, a second attached position whereby the end portion is displaced from the end of the cylindrical portion so as to allow ingress of a liquid into contact with the electrolyte in the chamber via the opening so that the electrolyte is suitable for allowing a potential difference to be generated between the conductive surface and the conductive rod of the battery.