Most problems with batteries happen when the inner coil becomes dirty. Please clean the battery inner coil from time to time with nail polish remover or pure alcohol, using cotton buds. The batteries will usually function normally afterwards. nikoBlue is the only manufacturer with an unlimited guarantee of exchange for the accumulator batteries. Of course, these small, slim batteries containing a great deal of technology in a very small space don't last forever, but their minimum life cycle is 300 recharging phases on average. However, if the battery falls to the ground, or if fine sand (on a beach) or damp get into it, it can suffer just like any other technical device. Sometimes the air intake opening may be dislodged, and you can try to clean it by blowing it out. In case the battery still does not function after taking these measures, please send the defective device to: Nikoblue.com Landgutgasse 26 1100 Vienna. We will send you a new accumulator battery straight away.