Eco-Drive is a model range of watches manufactured and marketed worldwide by Citizen Watch Co., Ltd. , powered primarily by light . As of 2007, the company has estimated the disposal of 10 million batteries in North America. 
Citizen introduced the Eco-Drive line to Asia, Latin America and Europe in 1995 and to the United States in April, 1996. 
The Eco-Drive concept introduced several technical refinements, including light-capturing cells that could be made virtually invisible behind the dial up of highly conspicuous, enhancing the appearance of the watch.
The technical platform that made the Eco-Drive concept possible was the Eco-Drive caliber 7878 movement. This movement was the first light-powered movement where the solar cells could be mounted under the dial. Previous light powered watches from Citizen and other manufacturers had the solar cell (s) mounted directly on the dial. Was this innovation enabled by marked improvements in Thin Film amorphous silicon solar cells, qui, by the early 1990s HAD Become Significantly more efficient. By locating a translucent dial material over the solar cells, enough light could pass through the face of the movement. Though the Eco-Drive caliber 7878 solar movement moves slightly visible through the dial, the physical styling of the light-powered watch was not longer constrained by visible solar cells.
To store electrical energy the first Eco-Drive movement employed titanium lithium-ion rechargeable gold secondary batteries . This battery type became available in the early 1990s, enabling an Eco-Drive 7878 movement to run 180 days on secondary power before requiring recharging via light exposure – a marked improvement in energy storage over previous light-powered watches. The movement also featured an “insufficient recharging” indicator. 
In addition to the first three Eco-Drive models introduced in 1995, Citizen marketed numerous other Eco-Drive models during the 1990s, including the 6.05 mm (0.238 in ) thick Eco-Drive Slim of 1996. 
Where the first models have been developed, features, and features, including complex analog and digital-analog movements and the chronological complications of chronographs , flyback chronographs and dive watches .
In the early 2000s, the United States continued to grow with the United States of America. Eco-Drive models have been received, generating a third of Citizen’s North American revenues by 2000. In 2002 the VITRO technology (VITRO Eco-Drive) came on the market, where the solar cells were no longer even slightly visible under the dial. During the mid-2000s, wristwatch sales improved for the Citizen thanks to further development of the Eco-Drive line and integration of radio-controlled timing with the 2002 Eco-Drive line. 
Eco-Drive Concept Models
Since 2009, Citizen has developed Eco-Drive Concept Models as technology and marketing tools. These Eco-Drive Concept Models are shown at exhibitions and produced in limited editions.    The Concept Model 2011 was the Eco-Drive SATELLITE WAVE that has a movement that can receive time synchronization signals from GPS satellites . This makes radio-controlled timing possible in remote areas that are not based on radio time signal stations.  In 2012 Citizen announced the Eco-Drive RING Concept Model. This watch features a ring-shaped solar cell surrounding the watch case sidewall.  
According to Citizen, by 2011 80% of their wristwatches featured Eco-Drive, and the company’s Eco-Drive type watches as the focus of new generations of watches. 
In 2012 Citizen offered over 320 Eco-Drive watches in various types, styles and price ranges. 
Light as power source
Most Eco-Drive watches are equipped with a special lithium ion lithium secondary battery packaged by an amorphous silicon photocell located behind the dial .  Light passes through the crystal and reaches before reaching the photocell. 
Depending on the electronic movement, it may be more expensive to use it, but most of the time it is worth it.  If kept from light for an extended period, some Eco-Drive movement models can hibernate, where the hands of the watch stop and the internal quartz movement continues to track the correct time. When will the right to be able to be paid, the hands move automatically to the correct positions and resume regular timekeeping. 
Temperature difference as power source
Citizen Eco-Drive Thermo watches were introduced in 1999 and use the temperature difference between the wearer’s arm and the surrounding environment as a power source. The rare Eco-Drive Thermo watches use the Seebeck effect to generate thermo electricity that powers the electronic movement and charges the secondary power cell. In the sun or in the tropics the ambient temperature can come close to the temperature of the wearer’s wrist the thermo electricity. In box no power is generated, an Eco-Drive Thermo movement will save power by moving the second hand in the second increments until the production of thermo electricity is resumed.  Citizen has stopped making Eco-Drive Thermo watches.
Hybrid Eco-Drive movements
Citizen also built an automatic quartz watch, the Citizen Eco-Duo Drive Promaster (released in December 1998).  Novel to this watch is the use of both mechanical power and solar cells. This model is an attempt to enter higher-priced markets (at a cost of around $ 1,000 USD). The Eco-Duo Drive technology failed to attract consumer interest.
Solar cell and battery life expectancy
According to Citizen, experimental data showed the solar cell and secondary battery for more than 10 years.  According to Citizen Europe, laboratory tests showed that after 20 years the secondary battery retains a capacity of 80% of its initial capacity. 
For water resistant and diving Eco-Drive watches Citizen recommends a watch gasket exchange every 2 or 3 years to preserve their water resistance because watch gaskets, which form a watertight seal, degrade as they age. Further, Citizen recommends maintenance for Eco-Drive watch movements in regular intervals in order to extend the life of the watch movement, since the gears used in running watch movements are subject to slow wear. Citizen states that their lubricants for Long-Lasting Precision Equipment when used in watches, timepiece movements remain smooth for a long time after 20 years. 
- Solar powered watch
- Jump up^ “Eco-Drive METAL Watches” . Citizen Watches Australia . Archived from the original on July 18, 2014 . Retrieved 12 February 2015 .
- Jump up^ “Celebrating 30 Years Of Environmentally-Conscious Watch Making -“. CSRwire.com, Mar 06, 2007.
- ^ Jump up to:a b “Citizen Holdings Co., Ltd.” . March 2011 . Retrieved 2012-04-22 .
- Jump up^ Instruction manual for caliber 7878 movements
- Jump up^ Eco-Drive History (1995-2009) (in German)
- Jump up^ Citizen BASELWORLD 2012
- Jump up^ Eco-Drive: Innovations for the Future
- Jump up^ Eco-Drive Concept Model
- Jump up^ 2011 Eco-Drive SATELLITE WAVE Concept Model
- Jump up^ 2012 Eco-Drive RING Concept Model
- Jump up^ 2012 Eco-Drive RING Concept Model
- Jump up^ Eco-Drive is designed for the Future
- Jump up^ CITIZEN Eco-Drive website
- ^ Jump up to:a b “EcoComp-pf06a_h01-04” (PDF) . Archived from the original(PDF) on 2007 . Retrieved 2009-08-22 .
- Jump up^ “History of the Solar Wristwatch” . Soluhr.com . Retrieved 2007-01-17.
- Jump up^ Loading properties of Eco-Drive watch movements (German)
- Jump up^ “Citizen Eco-Drive Thermo watch” . Pmwf.com. 2004-02-13. Archived from the original on 2009-08-08 . Retrieved 2009-08-22 .
- Jump up^ “History of CSR Activities” . Citizen Watch Co. Archived from the original on 2007-02-23 . Retrieved 2007-01-18 .
- ^ Jump up to:a b Citizen Service & Support FAQ Eco_Drive
- Jump up^ Citizen Watch Europe GmbH:ECO-DRIVE Technology(German) (archived 2007)
- Jump up^ “Products for CITIZEN” (PDF) . Retrieved 2009-08-22 . [ dead link ]