We don't recommend carrying batteries in your pocket or wallet.
Do not carry loose hearing aid batteries in your pocket as the heat from your body will cause peel-off tab be dislodged. Once the tab comes off the battery will be activated. Within 4 to 6 weeks, the battery will have lost all charge. There have also been reports of electrical shocks when loose batteries make contact with metal products such as keys and coins.
Even if the batteries are left in their packaging, the heat from your body combined with the pressure exerted on the batteries can cause the tabs on the batteries to become dislodged and activate the batteries.
We recommend carrying your batteries on your key ring using a battery caddy with the tabs facing down.
There have also been unconfirmed reports that the batteries can interfere with the magnetic strips on debit / credit cards as well as when using Pay Wave card (whilst still in the wallet).