It is an obvious idea to use the athlete’s motion to produce electric energy to continually recharge batteries. End of July 2016 the European Patent Application (EP 3 037 142 A1) by TUM inventors Senner and Schott was published. This patent with the title “A System for harvesting electrical energy during ski touring“ is now entering the marketing phase and can be licensed or purchased world-wide and at wish exclusively by sporting goods industry dealing with wintersports equipment. Please find further information here