They have to be activated by pulling off a tab etc. Then they wear out even if not used.
◦ Highest capacity-to-volume ratio for miniature batteries.
◦ Relatively flat discharge curve.
◦ Essentially constant internal resistance.
◦ Activated by removing covering (adhesive backed tab) from air access hole.
◦ Most effective in applications that consume battery capacity in a few weeks.
◦ Must have access to air (oxygen) to operate.
◦ Nominal voltage of 1.4
◦ Excellent service maintenance prior to tab removal.
◦ Available in common hearing aid battery sizes.
◦ Contains no added mercury.
They are 1.4V, no load immediately after activating. They quickly drop to about 1.28V (depending on temperature moisture and impurities probably)
I guess now these cells will be flat in 2 weeks now they are opened?
But it is VERY flat. Alkaline are about 1.6V fresh, no load and drop quickly to 1.5V, then average about 1.4, dropping gradually to 1.2 then rapidly to 0.9V end point.
Zinc Carbon Alkaline are almost 1.7V no load if very fresh and drop quickly to 1.4V, then average about 1.3, dropping gradually to 1.25 then rapidly to 0.9V end point.
Mercury and Silver Oxide are very flat discharge. Zinc Air are really a replacement for Mercury (toxic) and Silver Oxide (expensive!).
Most batteries it's only a "customary" nominal value that is quoted. 12V car batteries used to be 13.8 and now close to 14.2 V in a car running. The 6.3 is half a "12V" Lead Acid NOT on charge. Hence some US 6.3V valves are "7" series rather than "6" series as rated up to 7V for 6V Lead Acid supplies.