Solar Watch Batteries

Do Solar Watches Need To Have Batteries?

Solar watches, as the name suggests, use the sun’s energy as their primary energy source. People consider these watches eco-friendly because they utilize a renewable resource, but that doesn’t mean they don’t carry a battery.

Solar watches use batteries to store power. These batteries are called secondary cells and are specifically designed to handle regular charging and discharging. These batteries can hold charge for a minimum of 30 days and as long as several years.

This article will explore the ins and outs of solar watches. It’ll explain how the sun charges the watches’ batteries and how long a single charge can last. Additionally, I’ll tell you all you need to know to properly take care of the watch, ensure it’s always charged, and know if you need to replace its batteries.

How Does a Solar Watch Charge Its Batteries?

To charge a solar watch, you must expose it to sunlight. These watches have a solar panel behind the crystal made from multiple solar cells. When the solar cells are exposed to sunlight, they absorb the light energy and convert it to electrical power, which is stored in the secondary batteries.

If solar watches didn’t have a battery, they would need constant sun exposure in order to function. As you can imagine, this would be very unpractical.

These solar cells absorb light from all light sources, including artificial ones like LED bulbs. However, the energy provided by bulbs will be drastically lower than that provided by the sun. Besides, you would be using electricity, which would miss the whole point of having a solar-powered watch.

That said, if it’s dark outside, there’s no reason not to take advantage of the lights that are already turned on to give some extra charge to your solar watch.

How Long Do Solar Watches Store Charge?

Solar-powered watches can run for a minimum of 30 days with only one charge depending on the model, with some models reaching as long as 8 years. However, there are many solar watch models with different types of technology, which affects their charge storage capabilities.

Solar watches use secondary cells to store their energy. Unlike a disposable battery such as a dry cell or button battery, a rechargeable battery is eco-friendly. It can be used for a long time by discharging and recharging it. Some models have high-capacity batteries that allow them to go for months without requiring additional charging.

There have been many improvements in solar technology over the years that have improved the efficiency of modern watches.

However, constantly frequently charging solar-powered watches puts stress on the battery, which may significantly shorten its lifespan. This is why some manufacturers give tips to keep your battery healthy for as long as possible, including how often to charge it.

How Often Should One Charge Their Solar-Powered Watch

While there’s no set limit to the number of times one can charge a solar watch, you can protect the battery by removing it from the light source after it is fully charged.

Under optimum lighting conditions, a full charge can take up to 3 hours to complete, and this charge can keep the watch up and running for close to a year, depending on the watches’ use and model.

However, many modern watches have various safeguards in place to protect batteries from damage due to overcharging. Some disable the charging function once there is sufficient power in the secondary cells. Others disconnect the solar panel from the central system, effectively stopping the overflow of electrons into the battery.

It’s essential to follow the manufacturer’s instructions in order to take the best care possible of the lithium-ion battery inside your solar watch.

How Do I Keep My Solar Watch Charged?

Solar watches are maintenance-free, eco-friendly, and require less frequent battery replacement than other battery-powered watches, but they can still lose power and die.

Keep your watch charged by exposing it to direct sunlight. Experts recommend keeping the watch in a cool area to avoid overheating, which may damage its internal components.

While any light source can work, room or artificial lighting is significantly weaker than sunlight and will take a long time to recharge the battery. You can place the watch on a windowsill or any other surface exposed to the sun’s light.

If it’s dark outside, you can place it on your office desk, under your room, or reading light while not wearing it. Putting it on your wrist, under a sleeve, or in a concealed area won’t allow the watch to charge.

Do I Need To Replace My Solar Battery?

You don’t need to replace your solar battery frequently. Many watch manufacturers advise their customers to replace their batteries after ten years. After this time, a rechargeable battery’s capacity and efficiency may deteriorate gradually.

Secondary batteries are robust and designed to keep power for many years. However, they are also prone to damage or deterioration. Worn-out mechanical parts or degraded oils may also shorten recharging cycles, which may call for a replacement.

It’s a good idea to occasionally check the inside of the watch for poor lubrication, loose screws, rust from dirt and sweat, and any other deterioration. If you take it to a technician, they’ll clean the dirt and sweat on hidden components, preventing a malfunction.

If your solar watch is nearing its 10 years of life or its battery is showing malfunctions, you can simply get a replacement. If it’s a Casio, I recommend the Casio CTL1025 Solar Rechargeable Battery (available on This battery has a long lifespan, so you won’t have to worry about replacing it anytime soon.


Solar-powered watches are unique and enjoy a longer lifespan than traditional quartz and battery-powered alternatives. They are an eco-friendly way of keeping track of time while never having to worry about them running out of battery. Solar watches can last for decades and require little maintenance.

To fully enjoy your solar-powered watch, take good care of it by charging it properly and replacing the battery when the ten years are due, even if it’s still in good working condition.

If you don’t know whether you should replace the battery, you can always take your watch to a technician.


Share this Post