A method for predicting service life of a battery unit previously used within at least one first application, the method comprising: assessing a battery capacity of the battery unit at an end of a first service life of the battery unit within the at least one first application, identifying a suitable second application for the battery unit by comparing the assessed battery capacity to given power requirements of at least one suggested second application, obtaining ageing data indicative of battery ageing of the battery unit in its at least one first application, predicting an expected second service life of the battery unit in the identified second application based on at least information relating to a planned usage of the battery unit in the second application and on the obtained ageing data from the at least one first application.