Eco-Drive is Citizen’s name for its range of light-powered watches. Light passes through the glass and the dial to reach a solar cell beneath. The cell charges a storage battery, so the owner does not need to have the battery replaced regularly. Citizen designed the watches to be kind to the planet.
How does an Eco-Drive watch work?
Light enters through the watch glass and passes through the dial before it reaches a solar cell. The cell turns that light into electrical power. A small electronic circuit then manages where the power goes. It moves power between the solar cell, a storage battery and the motor that turns the hands. The battery stores power so the watch can keep running. In one model, a rechargeable lithium battery let the watch run for about six months on a single full charge.
Where it comes from
Citizen began work on light-powered watches because it wanted a watch that was gentle on the environment and free of routine battery changes. The caliber 7878 movement made the Eco-Drive concept possible. Citizen says it first used the name Eco-Drive in 1994, and that the name became a core part of the brand. Citizen also says the name was chosen to suggest technology that is gentle on people and the planet. The line went on sale in Asia, Latin America and Europe in 1995. It reached the United States in April 1996.
How is Eco-Drive different from earlier solar watches?
Light-powered watches existed before Eco-Drive, both from Citizen and from other makers. On those watches, the solar cells sat on top of the dial, in plain view. Eco-Drive moves the cell beneath the dial. Light reaches it by passing through the glass and the dial itself, so the cell does not have to be on show. Citizen also made a related line, Eco-Drive Thermo, launched in 1999. It is no longer made.
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