Eco-Drive is a brand name owned by Citizen Watches. As the name suggests Eco-drive wristwatches are powered by light. Eco-Drive wrist watches never needs a battery because these watches take light as the source for power. Eco-Drive watches were introduced in the market in 1995 by the Citizen Watch company.
The history of solar powered watches can be traced back to 1972. The twenty-four years between 1972 to 1995 can be called period of solar watches. This span of twenty-four years has witnessed many historical collectible watches such as the Synchronar, Nepro and the Sicura LCD. This all changed after introduction of the Citizen Eco-Drive brand watches in 1995. This significantly changed our perceptions about light powered watches.
What Exactly Citizen's Eco-Drive Watches are? The Eco-Drive technology is geared with a titanium lithium battery, which gets charged by amorphous silicon made solar cell, which is located behind the dial of the wristwatch. This special battery type doesn't get affected during charging / discharging cycles and is durable enough for a long life cycle. The Citizen watch company claims that even after 20 years of use, the secondary battery retains a power storage capacity of 80% (Source: Citizen Europe, Laboratory tests). When the watch is exposed to the light whether sunlight or any type of light, the light passes via the dial of the watch and reaches to the solar cell underneath dial, charging the battery of the wristwatch.
Having said that, usually typical office light is not enough for these watches to get a fully charged battery. It is advisable and recommended to use natural outdoor light to achieve the full charge. However the office or home light conditions are good enough to keep these watches continually charged.
Usually typical eco-drive models can operate up to 30 days to 4 years without further charge needed depending on the electronic movement and the model of the watch. Some of the models keep the internal quartz movement still running even if the watch is kept in dark for long time. Though hands of the watch stops when kept in dark for too long, but since the internal quartz movement is still running, the hands will move to the current time and resume functioning as before when the watch is exposed to the light again.
Another revolution with the citizen eco-drive has been the introduction of eco-drive thermal watches. The eco-drive thermal watches takes temperature difference as power source. Interesting isn't it? Now how does it work? well, these watches take the source of power from the temperature difference between the arms where it is wore and the surrounding environment. Woeehhh, but how? Well this very special Eco-Drive thermal wrist watches use the proprietary technology to generate thermo electricity to charge the secondary power cell or battery within the watch. The wearer's arm temperature is always higher than the surrounding temperature except in the sun or may be in the tropic regions. But what's best, even those times when you are out in the blazing sun or on a vacation to tropical region, this amazing eco-drive thermal watch will save power via it's power saving features until the production and generation of thermo electricity is resumed.
So yes, you can use both light and thermo electricity to power a watch. Eco-Drive watches have been quite a success with the inbuilt features and trendy technology.
While talking about Citizen Watches especially Citizen Eco-Drive and Thermal Watches, citizen also introduced Citizen Eco-Duo Watches. Now what's Eco-Duo watches? Well as the name Eco-Duo tells, these watches used both i.e. mechanical power and the solar powered cell to power the electronic movement of the watch. Because of this dual energy source, these watches can also be called as Hybrid Eco-Drive movement watches. But this models from citizen failed to attract customers because of high pricing (Were available for a grand and higher).
Eco-Drive watches are definitely interesting and technologically advanced time-keeping equipment. But in the modern days the watches are becoming more of jewelry and not for their time-keeping values. Thus I am not sure as how many buyers are really buying eco-drive watches for the ecological benefits of light powered watches implying less waste and lower energy requirements and time keeping.
Eco-Drive technology also provides fuel to the theory of disposable watches. But as mentioned above with watches being considered as jewel and a showpiece, not sure how far the progress with disposable watches will go?
Before ending this post here, I would like to share a interesting fact here, Amid all the watch brands and watches available world over, Citizen's Mens Titanium Skyhawk AT Flight Chronograph (Model Number JY0010-50E) has been the most selling watch in the year 2007-08. Citizen Watches are visibly emerging with top time peices which are affordable these days unlike the older times.
