Solar Watch Batteries: Everything You Need to Know


Repairing a Watch

A solar watch is a great way to reduce your reliance on disposable batteries. A solar watch battery can last for years with proper care, and it’s a great way to help the environment! 

In this article, I decided to focus on questions related specifically to solar watch batteries, as that seems to be a frequently searched topic that people are trying to troubleshoot. For more general questions about solar watches, check out this other article.

Do Solar-Powered Watches Need a Battery?

Generally, a solar-powered watch has to have a battery even if the manufacturer claims that their watch doesn’t use a battery, they’re still using a battery, even if you go off of the loosest definition of the word. 

For instance, Citizen claims that their Citizen Eco-Drive Solar Watch doesn’t use batteries. They use a series of solar cells that are rechargeable and store that charge for long-term use. They call it their “light-powered technology.”

The truth is, however, that they just defined what a battery is, and even in their user manual, they refer to these “solar cells” as “secondary rechargeable batteries.” Ultimately, if it stores energy…which is an essential function in a solar watch…it’s a battery, and all solar watches need one. 

Using the Eco-Drive example, the watch functions exactly like a typical solar watch would function, but the solar cells are designed to hold the charge, rather than simply converting it and sending it to a separate battery.

The result is a more efficient solar watch, but the solar cells still sit beneath the display and absorb natural and artificial light that is then converted to the energy necessary to fuel the Eco-Drive watch. 

How Long Does a Solar Watch Battery Last?

Typically, solar watch batteries are usually rated to last around 10 years, however, a lot of that depends on usage. Even if you overly strain the watch’s various functions, you should still get a good 8 or 9 years out of it. 

Batteries are rated in terms of cycles or, how many times the battery can be recharged until it degrades to an efficiency…in terms of recharging…of less than 80%. Once the recharging efficiency is less than 80%, it’s time to change the battery if your watch supports that function.

Of course, you can hold onto the watch as is and continue to recharge it for an additional 20 years. It will never hold that robust level of charge that it once did, but it should still give you a full day of activity, assuming that you are working in a cave or a mine, well away from any kind of light. 

If you think about it, ten years is a really long time for a battery to last, and there are usually a lot of functions on a solar watch that is accessible throughout that long decade, not to mention all of the benefits of wearing and using a solar watch.

  • No need to replace batteries for a decade
  • Very little maintenance required
  • Solar watches are very affordable
  • Solar watches are also very environmentally friendly
  • They are almost always charging

The best part about a solar watch battery is that it is almost always charging, thanks to the fact that the technology is able to derive energy from almost any light source. Unless you are laying in bed with all of the lights off, and your arm under the covers, it’s likely that your solar watch is pulling energy from something.

You would think that this would put an enormous strain on the battery, burning through its cycles almost constantly. However, the technology is what it is and solar energy…when applied this small…is incredibly efficient and long-lasting. 

Since many solar watches are so affordable, you’re getting a lot of short-term and long-term value when you purchase one. Low prices encompass the short-term benefits while the sheer longevity of the battery and watch offers all of the benefits of an affordable, long-term value. 

Changing a Watch Battery

Can You Replace a Solar Watch Battery?

Most solar watches support battery changes. However, the odds of having to get the battery changed out are slim and low. These watches are designed to last for so long it’s likely that they will be lost or replaced by the time ten years or more has gone by.

The problem is, outside of something that would necessitate a battery change, is it’s not something that you’re going to do be able to do on your own. At least not ordinarily. It’s a lot more complicated than removing the backing on a standard watch. 

For instance, if you take a look at this watch battery changing kit, you’ll get a good idea about where I am coming from. Of course, changing a solar watch battery isn’t going to require the use of all of the tools that you will find in that link. 

But it will require a lot more than you think and, unless you happen to be a watchmaker or designer, it’s probably best to take your watch down to a professional who can get in there and change the battery for you. 

The other problem with doing it yourself is that you may accomplish the battery swap without a hitch, reassemble your watch, and discover that it is no longer working. The parts within a solar watch are incredibly delicate, especially the tiny solar cells. 

That’s not to mention the fact that the tiniest electrostatic shock can easily destroy everything inside the watch without making a single scratch. You would have no idea until after you reassembled it. 

A professional, such as a watchmaker, will have all of the tools and protective equipment necessary to efficiently and expediently disassemble and reassemble your watch with your new battery installed and without leaving a sign that the watch was ever opened.

What Is The Difference Between A Quartz And Solar Watch Battery?

In general, the difference between quartz and solar watch batteries is that a quartz watch battery is powered by electricity, while a solar watch battery derives its power from light. 

So the biggest difference is between quartz watch batteries and solar watch batteries is how they get their power…but there are a few others:

  • Quartz Watch Batteries Don’t Last As Long
  • Solar Watch Batteries Don’t Need To Be Disposed Of Nearly As Often

A quartz watch battery will last for two to three years on average, while a solar watch battery can last upwards of ten years or more. 

Solar watches are also more environmentally friendly, as they do not rely on disposable batteries that can often contain harmful toxins.

Watch in the Sun

Can I Use Any Light To Charge My Solar Watch Battery?

In order to charge a solar watch battery, the light needs to be direct and bright. So while you may be able to get some juice from a lamp or other indirect light source, it’s not going to be enough to fully power your watch. 

Ideally, you want sunlight…which is why they’re called “solar” watches in the first place. But any light source will produce a small amount of power that can be stored in the battery for later use…similar to how the small solar panel on most calculators work.

Will Leaving My Solar Watch In The Sun Damage The Battery?

Leaving your solar watch in direct sunlight for short periods of time won’t damage it in fact, that’s the best way to fully charge your solar watch. However, direct sunlight for several hours could potentially overheat your watch.

Having your solar watch overheat means that there is a risk of damaging the internal components, so it’s best to keep an eye on your watch if you’re going to be leaving it in the sun for an extended period of time.

In general, it’s best to keep your solar watch out of the sun when you’re not wearing it. This will help to ensure that the battery lasts as long as possible.

Final Thoughts

Solar watches are a great way to reduce your reliance on disposable batteries, and they’re perfect for people who want to be environmentally friendly. 

While you may need to take your solar watch to a professional in order to change the battery, it’s definitely worth it in the long run. And with careful use, your solar watch battery should last for years…perhaps even decades!

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