Abstract: A method for detecting a self-discharge fault of a device battery of a technical device and its criticality includes (a) providing at least one operating variable curve of at least one operating variable of the device battery, (b) determining at least one operational feature based on the at least one operating variable curve, (c) detecting a self-discharge fault based on fault criteria depending on the at least one operating feature, (d) determining a criticality of the self-discharge fault depending on which of the fault criteria are met, and (e) signaling a self-discharge fault depending on its criticality.

Abstract: The disclosure relates to a method for providing an aging state of a device battery of a battery-operated device including detecting curves of operating variables of the device battery and providing at least one load factor at a determination time, providing a correction model that maps a correction variable depending on the at least one load factor, and ascertaining an aging state by evaluating the curves of the operating variables with the aid of an aging state model or an aging state observer or an aging state measurement and depending on the correction variable resulting from the at least one load factor of the device battery of the battery-operated device at the determination time.