New Duracell 312 hearing aid batteries with low voltage

[Peter_O]

Problem solved by BradC:
https://www.eevblog.com/forum/reviews/new-duracell-312-hearing-aid-batteries-with-low-voltage/msg5840697/#msg5840697
Zink air batteries need air to develop the full cell voltage.
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For my mum I regularly buy Duracell 312 hearing aid batteries.

They seem to be produced by Varta now.
The print on the plastic trays (for 6 batteries) has changed.



They are 1.45 V nominal.
But I'm measuring 1.05 to 1.1V with my Siglent DVM.

I suspected, it might be some forgery product and get another 60-pack from another shop.
Same 'new' print. Same low voltage.

Any hint or experience?

[BradC]

Any hint or experience?

Take the tab off. They are zinc-air batteries and won't actually develop the chemistry until they are exposed to air. It's really a one shot thing though, so you take the tab of 10 mins before you shove them in the hearing aid and they last a couple of days.

[Peter_O]

Now it's 1.44V 

Thx a lot, BradC!   

...for closing my educational gap.