Hearing Aid Battery Testers
Hearing aid battery testers are actually of limited value for the consumer, as they can only determine if the battery is actually dead.
In other words, because the discharge curve of a zinc air battery is virtually flat, the tester is unable to determine how much life is left! It is possible that the battery tester will indicate good when there is really only 10% of the service life left.
Some battery testers have wire leads, so they can be placed on the battery surfaces while the tab is in place. I recommend that battery testers should be designed so they can determine if the battery is good when it is tabbed. Interestingly, a tabbed battery will have a lower voltage and therefore, some testers will indicate that the battery is ''bad,'' even though in most cases the battery will work in the hearing aid.
If your tester has determined that a majority of your batteries are ''bad'', I would try them out in the aid before I would discard.