Solar Powered Watches – What Are They & How Do They Work?

Bering solar powered watch with titanium case and bracelet

Many people think that Solar powered watches (sometimes called a Solar Quartz watch) are a new thing but they were actually first seen in the 1970’s – although they were a little whacky-looking back then.

The first solar watch was introduced by Riehl Time Corporation and had large solar cells on the dial and the digital display was displayed at the side of the watch.

They have definitely improved in design in recent years with some of the mainstream brands bringing out some fabulous-looking watches.

What is a Solar Powered Watch?

A solar powered watch is one which uses a rechargeable battery to power the movement. The battery is recharged by converting light energy into electrical energy, absorbed in the solar cells in the dial of the watch.

How Long Does A Rechargeable Battery Last?

Most batteries in solar powered watches last between 7 and 12 years and some have been known to last up to 20 years! Compared to a normal watch button battery, which will last a year or two (particularly as the batter ages),

Solar Powered Watch Movements

A watch is powered by a movement inside the case of the watch. Watches can either have a mechanical movement (where the watch movement is powered by winding it up or by moving the watch) or a quartz movement (where the watch movement is powered by a battery).

Quartz movements are in most watches and are hugely popular based on their accuracy and ease of use. Once the watch is set you can just forget about it until the battery should go flat.

The battery in a quartz watch though starts off full-charged and very gradually drains over a period of a year or two (a little longer for new watches), until ‘flat’.

This is where the battery has no more energy charge and the watch movement will stop. It is easily replaced by your local jewellers and is fairly inexpensive. But the battery will need to be replaced again and again for the life of the watch.

A Solar powered watch, on the other hand, is a normal watch with a quartz movement but it is powered by a rechargable battery. The battery is recharged by light.

How Often Does a Solar Powered Battery Need Replacing?

Solar powered batteries will need replacing eventually but we are talking multiple years (as in, around a decade!) rather than a year or two with a normal watch battery.

There is a battery reserve in the solar powered watch which means it can last between 6-12 months even if kept in the dark.

A solar powered battery will only need to be recharged when there is insufficient light to charge the back up battery. The battery can be continually recharged until it deteriorated and will need replacing.

This normally happens around 12 years old but can be needed anywhere between 7 and 20 years.

What is the Best Way of Recharging a Solar Watch?

Just because the battery in a solar watch is recharged by light being absorbed on the solar cells under the glass of the watch, this does not necessarily have to be direct sunlight – it can be any light.

This could be a cloudy day or even left under an artificial light. Leaving your solar watch under bright natural light will quickly recharge it, but don’t leave it in direct summer sunlight or allow your watch to get too hot in the sun.

Are Solar Powered Watches Any Good?

Solar powered watches are very good and their accuracy is superb. Whilst an ordinary watch battery deteriorates over time, with a solar watch there is no deterioration of the watch battery charge for the watch to start loosing time or ‘winding down’.

Different Light Strengths Used to Recharge A Solar Powered Watch

“Illuminence” is the intensity of light that falls on a space and it is measured by something called lux (lx).

#Label
  • Direct summer sunlight is 100,000 lux (lx)
  • Full Daylight is 10,000 lux
  • An overcast day is 1,000 lx
  • A general office lighting is 300-500 lx
  • Twilight is 10 lx
  • Moonlight is less than 1 lx
  • (Source: Bioslighting.com)

Pros of Solar Powered Watches

  • Accurate
  • Conventional Looks
  • No battery replacement for many years
  • Keeps the watch seal intact (no watch back removal needed to get to the battery)
  • All the advantages of a quartz battery-operated watch with without the frequent battery renewal
  • Battery charge indicator on the dial

Cons of Solar Powered Watches

  • More expense (although not by much these days)
  • More expensive battery (approximately £28 compared to £5 for a normal button cell battery – our prices)

Excellent Solar Powered Watch Brands

Most of the well-known watch brands now have some solar watches as part of their collection. The famous and much-loved Citizen Eco-Drive watches are treasured by their owners.

Seiko also do some nice Solar watches.

Bering Time have some lovely solar watches. Famous for their slimline designs and minimalist looks they use scratch-resistant, sapphire crystal glass and medical grade stainless steel or titanium straps and case.

Casio G-Shock, a well-known workhorse of a watch that seems to withstand most things and are also available in a solar version.

To Sum Up

There has never been a better time to purchase a solar powered watch and it is an excellent choice if you want a watch which not only looks great (there are now plenty to chose from), but will keep its accuracy, has little upkeep or maintenance and you can just put it on and forget about it.

The only difficult thing is, which one…

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