Kinetic, or hybrid automatic/quartz watches, are timepieces that require neither winding nor battery replacement. Instead, these watches manufacture their own electricity from the kinetic energy produced by the wearer's movement, which allows them to charge their own batteries. These devices are hailed for their precision and energy-saving qualities, factors that have contributed to their sharp rise in popularity.
Kinetic energy is the energy of motion. In other words, it is power produced through movement. This type of energy, as created by the body's movement, powers kinetic watches.
As the wearer's body moves, oscillating weights within the watch rotate. This movement first becomes a magnetic charge. Then, as the magnetic field turns past a wire coil, it stimulates an electrical current in the wire. In order to keep the electricity from flowing back and canceling itself out, the weight is set off center. This means that it always falls in the chosen direction, creating positive net energy and charging the battery.
A fully charged kinetic watch can store energy for as many as six months without requiring a re-charge. The watch's main capacitor stores the energy, simultaneously keeping track of the correct time. Usually, the watch will "go to sleep" after about 24 hours of inactivity. When it is reactivated with a little kinetic energy, the time is reset according to the capacitor's calculations.
Additionally, many kinetic watches have indicators to let the wearer know how much charge is being held within the timepiece.
Kinetic watches require maintenance every seven years or so. The battery won't need replacing, but the watch will need a new main capacitor, which stores energy and keeps time.