Disclosed herein, among other things, are methods and apparatus for detecting battery chemistry or battery type and reconfiguring a hearing assistance device based on the detected battery. One aspect of the present subject matter relates to a method of operating a hearing assistance device having a battery. A voltage of the battery is detected at a predetermined load current and a battery chemistry or battery type is determined based on the detected voltage. An operating parameter of the hearing assistance device is adjusted based on the determined battery chemistry or battery type, in various embodiments. Examples of adjustments made based on the determined battery chemistry or battery type include gain, feedback cancellation (FBC) filter, self-diagnostic thresholds of the hearing assistance device, indicator loudness, low battery set point, or an end-of-discharge battery set point.