Citizen Eco-Drive

Citizen launched the first commercial solar-powered analogue quartz watch in 1976 (the Crystron Solar Cell). The Eco-Drive name was registered in 1995. The system uses a small photovoltaic cell positioned beneath the (translucent) dial; ambient light passes through to the cell, generating electricity that charges a rechargeable lithium-ion battery. The mechanism eliminates the standard battery-change service that normal quartz watches require every 2-5 years.

Eco-Drive variants differ by additional features. The base Eco-Drive is a quartz analogue. Eco-Drive Atomic adds radio-controlled timekeeping (synced from atomic-clock signals broadcast by national time services). Eco-Drive GPS uses GPS satellite sync. The Calibre 0100 (2019) is Citizen's high-grade Eco-Drive at ±1 second per year accuracy.