As part of a predictive diagnostic model, the Future Load Model is being used to predict future loads (time series data) that significantly influence the remaining lifetime of the lead-acid battery. For this purpose, past sensor data of the battery are first stored and grouped into representative load cases using unsupervised machine learning methods. Then, a feedback neural network (RNN) based on a so-called long short-term memory (LSTM) is trained and being used to predict future signal data. The now predicted data is assigned to the representative load cases by a classifier, e.g. Random Forest. By using the scattering of the data points within a load case, the confidence intervals of the predicted signal data are derived. Now the remaining lifetime can be calculated based on the future loads.