The history and development of the Citizen Eco Drive Watch
The citizen eco drive watch line came about as the result of Citizen being one of the few companies to really devote a lot of time and resources into the development of solar powered watches. The Citizen eco drive watch was introduced on the market in 1995. Before their introduction, the market was made up of solar watches that were similar in design and technology to the first solar watches using visible solar panels. With the introduction of the citizen eco drive watch peoples opinions of what solar watches were like changed.
A Citizen eco drive dive watch, the Promaster
The Eco drive explained.
According to Citizen, the power generation and storage system used in the Citizen Eco drive watch is the most technically advanced on the market. They utilize a Quartz movement which is powered by the combination of solar conversion and an energy cell (rechargeable lithium battery) any light source can be used which means there is a limitless free supply of power.
Solar panel
A disc of amorphous Silicon microns thin is used under the dial to convert light into electrical energy by way of the photovoltaic process.
This energy is then stored in the special energy cell and used to power the Quartz movement.
Energy Storage
Since the primary source of power is from light sources the energy cell is often referred to by Citizen as the “secondary battery” which can be misleading. The special titanium lithium-ion constitution of the battery makes it unaffected by the usual charge/discharge cycle that affects typical rechargeable batteries and tests showed even after 20 years batteries retained 80% power capacity*
Furthering their environmentally friendly credentials, these special batteries contain none of the chemicals found in typical watch batteries. A typical quartz watch will use a silver oxide battery which is used until depleted and then discarded. Citizen states that the battery used in their eco drive watches will give a lifetime of use.
Low charge Mode
As an indicator of low power the citizen eco drive watch has a “low charge warning mode” when this occurs the secondhand starts to move in two second increments instead of one, whilst still keeping the correct time. If the watch has more advanced features such as a chronograph, this function may temporarily be disabled.
If the citizen eco drive watch is put away where no light is available to it while in a fully charged state, depending on the model, it will run for from 45 days to 5 years. Most models also come with a 180 day power reserve.
Hybernation Mode
If a citizen eco drive watch is kept in the dark for an extended period it has a hibernation mode in order to conserve energy. The second hand sets itself to the 12 O’clock position but the internal quartz mechanism continues to keep track of time.
When exposed to light again the hands move to the correct time and normal time keeping is resumed.
Charging
Through normal day-to-day use a citizen eco drive watch will remain fully charged, however should power become depleted and it require supplemental charging Citizen recommends using outdoor light. The approximate charging times according to Citizen are for a cloudy day:9 hours; Sunny:3.5. After the watch has been fully charged from a low power state it will need to be set to “All Reset” mode or it will not run properly, this is achieved in different ways depending on model, please refer to the manual.
Precautions.
Its important not to subject the watch to temperatures above 140 degrees Fahrenheit, this could be an issue if for example you charged your watch leaving it on the dashboard of a car or positioned it too close to a regular light bulb (closer than 20″) or used a Halogen lamp.
Exposure to strong magnetic fields can cause the watch to start displaying the incorrect time. That means keeping the watch away from large tv’s, microwave ovens, computer monitors, cell phone speakers.. anything with a magnet in such as magnetic coin trays and so on.
Water
Subjecting the watch to sudden changes in water temperature can compromise the sealing capabilities of the gaskets allowing water to enter the watch. The heat can also cause certain watch elements to deform which could lead to mechanical failure. Its therefore best to avoid wearing the watch in hot tubs, jacuzzi’s and saunas.
* Source: Citizen Europe