Hearing aid batteries last approximately three to 22 days, depending on how often the person uses the hearing device, the type of hearing device, the type of battery used in the hearing device and the battery's capacity, according to Starkey Hearing Technologies. Zinc batteries last the longest, reports Audiology Online.
Hearing aid batteries come in five sizes, as of 2015: 5, 10, 13, 312 and 675. These sizes contribute to the amount of time that the battery lasts, according to Beltone. In order to increase battery performance, manufacturers recommended keeping batteries at room temperature when storing and not placing batteries next to metal items such as keys or loose change in a purse or backpack.