Battery voltage in open circuit condition is called the open circuit voltage. The open circuit voltage of the battery is equal to the battery voltage (that is, when there is no current through the Poles) battery positive electrode potential and the negative difference between the electrode potentials. Open battery open circuit voltage v, v = ф +-ф-open, φ +, ф-battery anode and cathode electrode potential, respectively. The open circuit voltage of the battery, are generally less than the EMF. This is because the poles of the battery electrolyte solution established by the electrode potential, usually are not equilibrium electrode potential, but stable and electrode potential. Can be considered the open circuit voltage of the battery is the EMF of the battery.