Solar Watch on Outdoor Bench

Do Solar Watches Charge on Cloudy Days?

One of the biggest worries people have about investing in solar products like solar watches is the availability of sunlight. This issue is a genuine issue for people who live in areas that are more likely to be overcast than not.

What happens to your solar-powered items in such conditions – for example, can you still charge your solar watch if it is cloudy outside?

Solar watches will charge on cloudy days. The significant difference will be in how fast the batteries will charge—the more direct sunlight solar watches (and other solar products) receive, the quicker they charge.

If you want to learn more about charging solar watches and other solar-powered items on overcast days, you’re in the right place. This article will answer all your questions, so keep reading for more information!

Solar Panels and Solar Watches Still Work on Cloudy Days

Solar watches essentially have an inbuilt solar panel in them. They use these solar panels to capture solar energy and photovoltaic cells to store them. You then use this stored energy to power your watch.

This storage system is relevant to charging your watch because solar panels continue to work on cloudy days.

However, they are less effective on overcast days than when the sun is out. Solar panels work about 10-25% as effectively as they operate on sunny days, depending on how cloudy the skies are.

The utility of solar panels on cloudy days is evident in the growing popularity of solar energy in famously cloudy cities like Seattle.

It also means that you can continue to use your solar watch when it’s overcast outside – it will continue to charge and work. 

If possible, you should carry a fully charged solar watch when leaving home on a cloudy day.

While your watch will continue to charge its batteries, it will charge at a much slower pace, increasing the risk that your timepiece will die for a short period before it recharges enough to start working again. 

Alternatively, you can look for ways to charge your solar watch that does not depend on natural sunlight.

Sunlight Alternatives To Charge Your Solar Watch

There are several ways you can charge your solar watch if there is not enough sunlight available, including:

Using Artificial Light

While sunlight is the best way to charge a solar-powered product – after all, it is free – if you don’t have access to sunlight, you can use artificial light to charge your solar watch.

It doesn’t matter what the artificial light source you’re using is, only that you aim the light directly at your watch’s face.

That said, it’s essential to remember that artificial light is a poor alternative to natural light. Your watch will charge very slowly when charged under artificial light—even a cloudy day offers speedier charging.

You can see this fact in the YouTube video below, which compares how much charge the same solar watch gets on a sunny day, a cloudy day, and under artificial light.

On a sunny day, the watch charges at level 10 (the highest charge). On a cloudy day, it is 4-5, but under only artificial light, it is 3-4.

Hand Crank Charger

If you’re facing an emergency and don’t have the time to let artificial light or indirect light do its job, you can use a hand-crank charger to charge your watch.

You can see an example of a hand-crank charger in the YouTube video below:

This charger is what it sounds like—it connects to your watch, after which you turn the crank until your watch charges to your desired limit.

It takes a bit of effort, but depending on how much charge you want and how badly you need it, it can be faster and more convenient than indirect sunlight on a cloudy day.

Another question to ask yourself is how likely you’ll require these solutions—how long does a solar watch last on one full charge, and how frequently do you need to recharge it?

How Long Do Solar Watches Keep Their Charge?

It’s important to note that you should not allow your solar watch to drain energy entirely unless you have no other option.

Doing so reduces the watch’s lifespan and will require you to replace it relatively quickly. Where possible, keep your solar watch at least 50% charged.

Like most other watches, the more functionality a solar watch has, the shorter its battery life. However, solar watches that tell the time and do little else have a relatively long charge.

For example, a full charge in a Casio solar watch lasts up to six months.

Of course, this isn’t the case for all solar watches. For example, a Garmin solar watch with the battery-save mode turned on will last 56 days on a full charge—a far cry less than the six months offered by Casio.

And, as mentioned above, if you enable added functionalities, the watch will stop working faster. For example, the same Garmin watch with GPS mode and wrist-based heart monitor will last only 30 hours.

Remember that these numbers rest on the assumption that you will charge the watch once and never charge it again until it runs out of power. In practice, this will rarely be the case.

Because a solar watch charges itself while you go about your daily life, they rarely run out of battery in practice. The genuine concern with these watches is the battery life.

Most solar watches have a battery life of about ten years, though you may need to see a watchmaker within 5-6 years, depending on how well you treat your watch.

However, this still gives solar watches a significant advantage over non-solar-powered watches—the watch batteries for the latter last only about two years on average.

Final Thoughts

Your solar watch will continue to charge during a cloudy day, though the charging speed will be significantly slower.

While this may be a concern if your solar look is low on battery, in most cases, you can continue to wear your watch without worry, regardless of the outside cloud cover.


Share this Post