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How does Eco-Drive work? Citizen Eco-Drive watches use the simplest, yet most technically advanced power generating and storage system in the Watch Manufacturing Industry. A Solar conversion panel and energy cell are the power provider for these Quartz Watches. Eco-Drive's ability to use light from any source to generate electrical power means that the supply is limitless and free. The absence of any added complex power generating machinery that would require additional upkeep is another big advantage.
•What is a Solar Panel? The Eco-Drive watch uses a microns thin disc of amorphous Silicon under the dial to convert light energy into electrical energy through the photovoltaic process. The electrical energy is then stored in a special energy storage cell . The charging is done in a more efficient manner than was ever before thought possible. Because of this newly developed technology, it is now practical to use a wide variety of attractive dials.
•How is Energy stored in the watch? A special Eco-Drive energy storage cell is used to store the electricity from the converted light energy. The high quality of the cell precludes it from being affected from the regular charge/discharge cycle as with an ordinary battery. With normal care and exposure to light, the owner can be assured of a lifetime of reliable and trouble free power. As an added benefit to the environment, the energy cell contains none of the chemicals used in ordinary watch batteries.
•How long will the energy storage cell last? With normal care the Eco-Drive Energy Cell will last a lifetime of use.
•Why does the second hand jump in 2 second increments? This is a low power warning function and indicates that the reserve power is getting low and the energy cell needs to be fully recharged by exposing it to light for a period of time outlined in your owner's manual. This may also occur after fully recharging your watch after a complete discharge of the energy cell. If you have fully charged your watch and the second hand continues to move in two second intervals, you need to do an all reset of the watch. For simple analog models, pull the crown out to the time setting position for 30 seconds, then return the crown to the closed position next to the case, then set the time. For multi-function models, please refer to your owners manual.
From -
http://www.citizen-watch.co.uk/technology.html#how