Solar Watch Maintenance

The "no battery change" promise of Citizen Eco-Drive, Seiko Solar and Casio Tough Solar is mostly true. But not entirely.

The 5-year service

• Secondary battery (capacitor) lasts 10–20 years. Eventually loses capacity.
• Gaskets dry out at the same rate as any other watch.
• Solar cell can yellow under heavy UV after 8–10 years.

Charging maintenance

• Don't leave a solar watch in a drawer for years — it can deep-discharge and damage capacitor.
• Once a month under any window for an hour is enough.
• For travel watches, 5 minutes of direct sun per week keeps it topped up.