What is an Eco-Drive watch?
Eco-Drive watches convert any type of light into energy
Japanese watch manufacturer Citizen developed a special type of solar watch with Eco-Drive technology.
Eco-Drive watches are designed to work with any type of light, including overhead lights or desk lamps. You can rely on your watch not to suddenly stop during the day.
With a full battery charge, most Eco-Drive watches are able to run for over six months in a dark environment. For optimal results, it is recommended to expose the watch to direct sunlight for five to six hours per month.
A Miniature Power Plant for Watches
- Light penetrates the dial.
- The solar cell converts light into electrical energy.
- The integrated circuit (IC) issues various instructions.
- The motor drives the watch hands.
- The secondary battery stores the generated energy.
Eco-Drive eliminates the need for regular battery changes. Since you can easily recharge your watch by holding it up to the light, you never have to worry about your battery running out.
The Special Features of Eco-Drive Dials
In many Eco-Drive models, the solar cell is located on the underside of the dial. Eco-Drive cannot generate electricity with an opaque dial, as no light can reach the solar cell. Conversely, if the dial is too transparent, the underlying solar cell becomes visible, which is not aesthetically pleasing. This is why Citizen focuses heavily on developing dials that are translucent (to allow light to pass through) but not transparent (to conceal the solar cell). The dials are designed to efficiently generate electrical energy even from a small amount of light.
Technology for Extended Light Output
The amount of energy that can be generated from light is naturally quite modest. It is therefore important that this energy is preserved for as long as possible. To reduce energy consumption, especially in models equipped with advanced, energy-intensive features, Citizen is continuously working on improving IC programming, circuitry, and motors. The story of Eco-Drive's progress is a story of steadily decreasing energy consumption.
Power Saving Function - Your Watch Sleeps in the Dark
If the watch has not been exposed to light for a certain period of time, the power saving function is activated. The hands stop moving so the system can conserve energy. Even with the power saving function activated, the watch continues to display the correct time internally. Energy generation resumes as soon as the watch is exposed to light and the hands start moving again.
*Not all models are equipped with the power saving function.
Low Battery Warning
When the watch's battery level gets low, the low battery warning function is activated. The second hand then moves in two-second intervals to indicate that the watch needs to be charged. However, the watch continues to display the correct time. Once the watch is sufficiently charged, the second hand will move again in regular one-second intervals.