How long should your batteries last? The best way to get a good estimate on what your battery life should be is for you to test the battery. Browse our large selection of hearing aid batteries. This Power One Zinc Air Batteries (1.45V )" is the ideal power supply, especially for todayÅ½s digital hearing aids. The air holes of the battery are initially sealed with a protective tab. They are kept in an "inactive state" until they are needed.