Abstract: A reserve activated electrochemical cell in which a reservoir containing a quantity of electrolyte is placed within an outer cylinder and is biased to force the reservoir to a predetermined active position. Restraining means are provided to restrain the reservoir in a second or reserve position remote from the active position. Upon removal of the restraining means the reservoir is moved to an active position and cell activation begins. Also included is an electrolytic cell to operably connect with the reservoir and valve means are provided between the cell and the reservoir to permit flow of electrolyte from the reservoir into the cell under pressure.