Solar Movement
A solar movement is a watch powered by light. A cell under the dial converts sunlight or room light into electricity and stores it in a rechargeable cell, so there is no routine battery change. Fully charged, it carries on running for months in the dark.
At a glance
- Energy source
- Sunlight and room light
- Battery change
- None, rechargeable cell lasts many years and can be replaced
- Dark reserve
- Months on a full charge
A solar movement draws its energy from the light that falls on it. A cell set under the dial converts both sunlight and room light into electricity and gathers it in a rechargeable cell, so the habit of routine battery changes disappears altogether.
How light becomes power
The cell under the dial charges quietly through the day, and the storage cell is built to last many years, often a decade or more, and can be replaced if it ever weakens. At heart it is a quartz watch that takes its energy from light instead of from an outside source.
What it gives you in practice
- No battery changes: with no battery to replace, that service item simply disappears
- Years of service: the rechargeable cell is built to last many years, often a decade or more, and can be replaced if it ever weakens
- Months of reserve: fully charged, it carries on running for months in a dark drawer
The best-known implementation is Citizen's Eco-Drive system, and Seiko makes solar watches of its own. You can explore the whole movement family in the Movement category, and read up on storied Japanese houses in our Best Japanese Watches guide.
Examples
Citizen's Eco-Drive is the best-known solar implementation and a sensible choice for anyone who wants a wear-it-and-forget-it watch with no maintenance.
View this watchSeiko makes solar watches of its own, so a light-powered movement is not tied to a single brand.
Comparison
A solar movement and a battery-powered quartz watch share the same accuracy; the difference is the energy source.
| Option A | Option B | Notes |
|---|---|---|
| Solar movement | Battery-powered quartz | Solar draws its energy from light that falls on it and needs no routine battery change; standard quartz relies on a battery that runs down and has to be replaced. |
Related terms
Watches that show this
Frequently asked questions
Does a solar watch ever need a battery change?
No, there is no routine battery change. A solar watch stores energy in a cell under the dial, and that rechargeable cell is built to last many years, often a decade or more, and can be replaced if it ever weakens, so the periodic battery change of a standard quartz watch simply does not arise.
How long does a solar watch run in the dark?
Fully charged, a solar watch carries on running for months in the dark. It would have to sit without any light for that long to stop, and in everyday use it draws in sunlight and room light continuously, so stopping is rare in practice.
What is the difference between a solar movement and Eco-Drive?
A solar movement is the general term for any watch movement powered by light. Eco-Drive is the best-known single implementation of it, namely Citizen's solar technology. Seiko also makes solar watches, so solar is not specific to one brand.