Posted on 二月 11 2025
Citizen’s Eco-Drive watches run on light. Sunlight, a desk lamp, the light in your living room: any light charges the watch, and a fully charged Eco-Drive keeps running for months in a drawer. There is no battery to replace.
What happens inside
Under the dial sits a thin solar cell. Light passes through the dial to the cell, which turns it into electricity. That power is stored in a rechargeable power cell, which runs a quartz movement, the same kind of movement found in a battery watch. You get the accuracy of quartz without the battery change.
Citizen made its first light-powered analog watch in 1976, and Eco-Drive marks 50 years in 2026.
How long a charge lasts
A fully charged Eco-Drive keeps running without any light for several months to several years, depending on the model. Models with a power-save function last the longest.
For most people, wearing the watch is enough to keep it charged. A watch that spends most of its time under a sleeve or in a drawer may need some time in the light now and then.
When it needs light
On many Eco-Drive models, the second hand starts jumping in two-second steps when the charge runs low. That is the watch asking for light, not a fault. Leave it in daylight and it returns to normal once it has enough charge.
How to charge it
- Daylight by a window charges it fastest.
- Indoor light works too; it just takes longer.
- Avoid high heat: don’t leave the watch on a car dashboard or right under a hot lamp.
If an Eco-Drive has stopped completely, give it several hours of daylight before you set the time.
Looking after it
The rechargeable power cell is designed to last for many years, so there is no regular battery change. Treat it like any good watch: rinse it with fresh water after salt water, and keep within its water-resistance rating.