A solar watch combines the long lifespan of a mechanical or automatic timepiece with the accuracy of quartz. This type of watch is becoming increasingly popular; Sustainable solar energy is hot! But how do solar watches work? What are the benefits of solar? And are they really that sustainable? In this blog we answer all your questions.
How does a solar watch work?
Just like quartz watches, solar watches operate on (lithium) batteries. Unlike the battery of a ‘normal’ quartz watch, the battery of a solar watch is charged by means of (sun)light.
There are small solar cells in or around the dial of the watch. Light energy is converted into electronic energy via a specially designed photovoltaic system, comparable to the operation of solar panels that are now on many roofs. This energy is stored in the rechargeable battery that powers the timepiece.
Furthermore, a solar watch works in the same way as a traditional quartz watch; with a vibrating quartz crystal in the electronic circuit, which ensures very accurate time indication.
Most solar watches also work on artificial light
The name suggests that a solar watch only works on sunlight. But while these watches charge best in natural light, most can also be charged via artificial light. It’s worth checking your watch’s instruction manual for more information on how your specific watch responds to different lighting conditions, as this varies from brand to brand. In general, the brighter and closer the light source is to the watch, the better.
The benefits of a solar powered watch
Solar powered watches are not only precise and reliable, other advantages are: high quality, durability and functionality. Enough reasons to add a solar watch to your collection.
Reliable: the precision of quartz with the convenience of an automatic
Because the battery of a solar-powered watch is continuously charged, it tells the time reliably and very precisely.
Functional and accurate
Because the energy source is in principle inexhaustible, it is possible to add extensive functions – which require a lot of energy – to the watch. That is why many solar watches contain radio control, GPS or Bluetooth that make the watch even more accurate.
High Quality
To protect the solar cell, solar powered watches are usually made of sturdy materials and are therefore of high quality.
Water resistance
Because the watch almost never needs to be opened to replace the battery, the rubber gaskets that protect the inside against water ingress do not wear out as quickly as with regular quartz watches. This ensures that the water resistance of a solar watch is guaranteed.
Sustainability
Solar watches are more durable than quartz watches with a disposable battery. On average, the battery of a solar watch lasts 7-12 years. These batteries can also be charged hundreds, even thousands of times before a replacement battery is needed. You also do not use mains power, as when charging your mobile phone, but energy from light.
This makes solar watches sustainable
Although the rechargeable battery of a solar watch lasts a very long time, it is of course still a battery. The production of batteries and the extraction of the materials used to make batteries are quite harmful to the environment. And when the battery is eventually replaced and thrown away, the chemicals can leak out and contaminate soil and water.
However, rechargeable batteries are a more sustainable choice because they require less material. If you maintain your watch properly and, for example, replace the strap instead of buying a new watch, you will be even more sustainable. This means that materials do not have to be extracted and produced again to make your watch.
Or when you buy a new solar watch, choose a watch made from recycled or sustainable materials such as bioplastic or recycled steel. You will mainly find these watches in the Skagen and Casio collections.
Disadvantages of a solar watch
So far we have only talked about all the benefits of a solar watch. However, there are also a few disadvantages:
With some solar watches, the solar cells are visible in the dial. This is something you need to address. Some people find this ugly, others like to show what kind of watch he or she is wearing.
Solar watches with a battery that lasts less long must be charged more often in the light. But if you ensure that you wear the watch regularly, every solar watch has enough energy to get through the day.
As far as I’m concerned, minor inconveniences compared to the benefits and no reasons not to choose a solar watch.
What is the lifespan of a solar watch?
With a full battery, a solar watch functions without light for one to twelve months, depending on the brand and model. Some brands guarantee a service life of up to 10 years in power save mode. Even in the dark! With most solar watches, a battery indicator shows when the watch needs light to charge again.
How long does a solar watch need to charge?
Although solar watches can be stored in the dark, it is best for battery endurance to store them in a well-lit place. This prevents the battery from draining completely, which can damage its lifespan.
How long the watch continues to work depends on how advanced the watch is. A watch that only tells the time requires less energy than a watch that has all kinds of other functions. Has the watch stopped completely? Then a few minutes of light is often enough to get the solar clock working again. It takes more time to fully charge the battery.
Average solar battery charging time table*
| Light source | Charging time for 1 day of use | Charging time for completely empty battery |
| Direct sunlight | 10-40 minutes | 18 hours |
| Fluorescent lamp at a distance of 20 cm | 1.5 -2 hours | 72 hours (3 days) |
| Interior lighting in surroundings | 5-6 hours | 120 hours (5 days) |
*please refer to your watch manual for charging instructions
The best solar watches at a glance
The best brands with solar watches in their collection are Citizen and Seiko. These two Japanese watch brands were and are forerunners in the development of solar energy technology for watches.
Seiko Solar watches
The first solar wristwatch in 1977 was from Seiko and the brand has continued to perfect the technology since then. Seiko Solar watches are still among the most popular in the world.
Citizen Eco-Drive watches
Citizen is also a pioneer in the field of solar watches. The Citizen Eco-Drive system is used in 80% of all Citizen watches. The Citizen L Solar women’s watches are produced entirely from sustainable materials.
G-Shock Tough Solar
G-Shock watches are almost indestructible, so the brand’s solar technology must also be strong and last a long time. The G-Shock Tough Solar models offer both power and longevity.
Garmin solar smartwatches
Garmin is a producer of very advanced and versatile smartwatches. In every line of Garmin smartwatches you will find models with a regular rechargeable battery and solar smartwatches. For example with the Garmin Instinct. How nice is it when you go out that you don’t have to worry about whether your smartwatch has enough energy for the entire trip?
How much does a solar watch cost?
How much a solar watch costs depends on the brand, the materials used and of course the functions, but on average count on 140 to 300 euros.
Solar watches are available at Techzle in all price ranges. You can get a simple plastic digital solar watch from Casio from 60 euros. At the other end of the spectrum you will find solar watches from G-Shock MR-G or the Seiko Astron with extensive functions such as GPS, radio control and Bluetooth, ranging in price from 2000 to more than 6000 euros.
Whatever budget you have, a reliable, accurate and durable solar watch is always a good investment!