The aging of batteries limits their life; this is a disadvantage for all devices powered by batteries, the aging study of Lithium-Ion batteries is therefore a key issue in the development of embedded applications including electric cars. In this paper, aging of commercial Lithium-Ion cells is studied under nine different conditions for up to 15 months. Test protocol and aging results are shown; these results have been used to develop an algorithm for real-time tracking of battery aging (SoHE). This new SoHE algorithm can be easily implemented to forecast batteries aging and there lifetime directly from a given power solicitation and temperature profiles. At the same time, it can be also combined with the calendar-aging model and finally used to recalibrate the State-of-Energy (SoE) algorithm.