1. Air is the other half
A zinc-air battery stores zinc and draws the other half of its reaction from the air. It gives about 1.45 volts and holds that voltage steady right through its life.
2. The tab covers the air hole
The sticker on the back seals a tiny hole. Peel it off and air gets in, the reaction starts and the battery begins to lose its charge. That is why the tab stays on until the minute the battery is needed.
3. Wait a minute after the tab
The first minute is when the cell fills with air and reaches full power. Put the battery in straight away and the hearing aid may not work properly, so give it a moment.
4. It keeps its charge while sealed
An unopened zinc-air cell can sit on a shelf for about three years and still be good. Once the tab is off it starts draining within hours, so keep unopened ones in the pack.
5. Never try to recharge one
The reaction cannot be reversed, so charging a zinc-air cell does nothing except make it leak. When it is flat, it is a new one.