How much power can the PowerWatch generate?In order to charge its internal battery, the MATRIX PowerWatch requires a temperature differential with the ambient air. It can generate more power when the air is cooler, and also when you are active and your skin is warmer. The PowerWatch will charge its battery most quickly when you are active (walking or running), and when the ambient temperature is below 80 °F. Above 90 °F, the PowerWatch cannot charge its internal battery. In the case that it is unable to charge, the watch will work for up to 1 year. Not covering the watch with a shirt sleeve, wearing the watch snugly on the wrist, and allowing the arm to swing naturally during physical activity will all boost the rate of energy production.