How do solar powered watches work? How do solar powered watches work?

How do solar powered watches work?

September 12, 2023 -

How do solar powered watches work?

Solar powered watches work by using solar cells integrated into the watch's dial or face, allowing them to absorb and convert any light source into usable energy, whether from the sun or artificial sources such as lightbulbs. This energy is the stored in a rechargeable lithium-ion battery, which powers the watch's functions.

How long do solar watches last? 

Most solar watches last between six months and two years, depending on model. With CASIO / G-SHOCK watches, just 8 minutes of direct sunlight gives you 1 days worth of power - any light source - artificial light such as lightbulbs or natural sunlight. Solar powered watches have a power reserve of up to TWO YEARS* (*times may vary, please refer to your watches manual). Power reserve refers to the amount of time the watch can store the power and operate whilst in the dark and not being charged. With CASIO’s reassuring power reserve your watch will keep working even if it’s in the drawer, a box or in a low light situation. 

If you are looking to try a timepiece like this for yourself, you can find all of our tough solar powered watches right here.

Can you replace the battery?

Tough Solar watches will never require a battery replacement as they are powered by light energy. Should you have any queries regarding the solar battery in your watch remember to contact Casio customer service who can assist with any questions or arrange for your timepiece to be inspected by a qualified technician.


Do solar powered watches need to be in the sun?

Solar powered watches don't necessarily need direct sunlight to charge. While sunlight is the most effective and strongest source of energy, these watches can also charge from various light sources, including indoor lighting. So, whether you're in the UK or spending time indoors, your watch can still charge. As for winter, solar watches can work in colder months too, as long as they're exposed to light. These watches are designed to adapt and maintain their functionality all year-round.

Tips for charging a solar watch (at any time)

  • Sunlight is best – direct sunlight is the most efficient way to charge your watch
  • Use indoor light – don’t worry indoor light or any artificial light works too
  • Regular wear helps – keep the watch on your wrist for regular charging
  • Brighter light, faster charge 
  • Store in well-lit areas if not worn daily 
  • Year-round charging – solar watches work even in winter
  • Read the manual – check the manufacturer’s guidelines for best practices.

Is a solar watch worth it? 

Absolutely worth it. Solar watches bring a host of benefits to you:

No battery changes (Saving money every year)

Power reserve ensures watch works in the dark for up to two years*

A constantly reliable source of power.


Upgrade your watch collection with our latest Tough Solar watches - shop the range now.