Your new hearing aid battery has not lasted very long because you did not wait at least one minute before using it, after you removed the freshness tab. The hearing aid battery changed in June of 2011. That is when most manufacturers removed mercury from the hearing aid battery to comply with state laws banning the use of mercury. If you haven't already noticed on the packaging of your hearing aid batteries, all are now mercury-free.
Today's zinc-air mercury-free hearing aid batteries need a longer time to fully activate, once the freshness seal is removed. Zinc air batteries use oxygen from the air as a source of power. The battery's ingredients begin to activate once the tab is removed and the air enters into the tiny pinholes. Zinc air batteries, previously with mercury, activated much faster and performed more consistently throughout their life. As a result, the new mercury-free hearing aid batteries take much longer to activate, and may not perform as well as they did when the batteries contained mercury.
Always buy the freshest batteries you can find. Hearing aid batteries have a four year shelf life from the date of manufacturing. In other words, to know when the battery was made, subtract four years from the expiration date on the package.
Store your batteries at room temperature, as heat shortens the life. It is not necessary to refrigerate them. Do not carry batteries loose in a pocket or purse, as metal objects (coins) may short them out. Instead use a "battery caddy" (a small plastic carrier containing 2 to 3 batteries). Ask your hearing aid specialist for one. You will find some of the freshest batteries at hearing aid offices.