<div class="htmlview paragraph">The need for deep diving submersibles, the advantages of batteries located outside the hull as power sources, and the place of silver/zinc batteries in this application are summarized. Environmental and operational factors which affect battery design and performance are discussed along with how the problems were overcome. State-of-the-art capabilities of silver/zinc deep ocean batteries are illustrated from data on several operational cells and batteries. It is concluded that this type of battery is suitable for deep ocean use and has the advantage of being already operational.</div>