Best solar watches

Everything a light-powered movement can do, in one case: chronograph, perpetual calendar, dual time, alarms, a slide-rule bezel and radio setting, behind anti-reflective sapphire and rated to 200m. It is the only watch on this site that is never wrong and never needs setting.

45mm is a genuinely large watch and the module is the whole watch — when the U680 stops being supported, no amount of case quality saves it. Buy it as a twenty-year instrument rather than a lifetime one.

It sets itself by radio, runs on light and is rated to 200m behind sapphire — and it is a module, not a movement. When the module stops being made, the watch is finished, however good the case still is.

The Speedtimer line is Seiko taking solar seriously: sapphire, a 41.4mm case at 45.9mm lug-to-lug, and a chronograph that runs on light. Seiko publishes a service price list covering solar calibers, which is more than any other brand here does for a light-powered watch.

The 21mm lug width is the irritation — an odd size that is stocked but costs more and takes longer, on a watch you may own for twenty years and restrap ten times.

Seiko lists V-series solar service at $163 — cheaper than a 4R36 overhaul and far cheaper than a mechanical chronograph. The 21mm lug width is the annoyance: standard straps come in 20 and 22.

Citizen's Super Titanium is surface-hardened, which addresses the one real weakness of titanium — that it marks more easily than steel — and the case is 44mm with a 22mm lug width. As a watch to put on and forget about for a decade, this is the shortlist.

Mineral glass is the cost, and on a 44mm dial that is a lot of surface to keep unmarked. Citizen does not publish a service price list, so what a module replacement costs is a quote rather than a number.

Citizen's Super Titanium is surface-hardened, which is the point — plain titanium marks more easily than steel, and this does not. It is the closest thing on this list to a watch you can stop thinking about.

The Promaster Diver is the default answer to "I want a watch I never touch": 200m of water resistance, a screw-down crown, a 20mm strap fitting and five years of cover, running on any light source including a desk lamp.

Mineral crystal again, on a 44mm case. If you want the same idea in sapphire you are paying considerably more or moving to the Seiko above and giving up 100m of rating.

The strongest argument for this watch is the one Citizen makes on its own page: nothing to replace, five years of cover. The argument against it is the mineral crystal, which will scratch where sapphire would not.

Sapphire on a Timex is rare and sapphire on a solar Timex at 36mm with 100m of water resistance is close to unique. At 44.5mm lug-to-lug it fits wrists that most solar watches do not, on a standard 18mm strap.

Timex states one year of warranty and excludes the crystal, strap, case and battery from it, which is the shortest and narrowest cover on this site. The watch is good; the paperwork behind it is not.

The smallest genuinely good watch here. Sapphire, solar, 100m and 44.5mm across the lugs — if you have a small wrist and want to stop thinking about batteries, start here.

The Chandler is the field-watch shape done as a solar quartz: 37mm, 100m, an 18mm strap and a dial you can read without thinking. It is the smallest light-powered watch here and one of the few that suits a 6-inch wrist.

Mineral crystal and no published thickness or lug-to-lug. Citizen tells you less about this watch than Seiko or Hamilton would, which is a recurring frustration with the brand.

37mm, 18mm lugs, 100m, no battery, five years of cover. There is very little here to go wrong and almost nothing that will date.