Everyone has had the need for a calculator at some point in their lives, be it at school, work, or for everyday calculation tasks such as doing their taxes. Most of us are very familiar with the common hand-held calculator used for these simple arithmetic tasks and probably have at least one laying around somewhere in our house. 

If you dig up your calculator, you are likely to find that as if by magic, it still works! Unlike many electronic devices that have very short battery life spans, calculators, and specifically solar-powered calculators have a long lifespan.

The introduction of solar-powered calculators in the 1970s was revolutionary and was seen as a sign of the world moving to renewable energy sources. Over the years, they’ve changed and progressed with technological advances. 

The current solar-powered calculators are smaller, cheaper, and faster than the first solar-powered calculators. They are extremely wide-spread nowadays, as most cheap calculators being sold are solar-powered. 

What Is A Solar Powered Calculator?

Solar-powered calculators are small, hand-held devices that use energy from solar cells to function. Solar cells, also known as photovoltaic cells, use energy from light (artificial or real) and turn it into electricity used to power the calculator.

Solar-powered calculators are very common, as nearly all basic calculators use solar cells. There are two main types of solar-powered calculators. The first is only solar-powered and does not have a separate or back-up battery. 

The second type is dual-powered calculators that have a small battery in addition to their solar cells. Solar energy is used to recharge or supplement this battery, extending its life significantly. 

More powerful calculators, such as graphing calculators and those that perform advanced functions, require too much energy and so are very rarely solar powered. These are usually lithium-ion battery powered and can be rechargeable, or not.

Do not be fooled! Some calculators have fake solar cells installed on them to make them look as if they are solar-powered when they really are not! It is thought that these fake solar-cells are added to give the illusion of solar power without the associated cost, although solar cells for calculators are very cheap to produce and so the savings are likely not that big. 

Note: Sufficient light is necessary for solar-powered calculators to work. If working indoors, ensure there is enough ambient light available to charge your calculator’s battery. If insufficient light is available, your calculator will not function or will rely exclusively on the back-up battery, if one is available. 

How Long Do Solar-Powered Calculators Last?

The purpose of creating solar-powered calculators was to make them long-lasting, so in general, they have a very long lifetime. Although a definitive lifespan is generally hard to pinpoint, a solar-powered calculator is likely to last 5-15 years, with many people claiming that their calculators have lasted them for over 20 years!

It is assumed that within 10 years your solar cell battery will only be charging to about 60% of its capacity. For a small calculator that does not need much energy, this charging capacity may be enough to sustain continued use of your calculator, but it indicates that its lifespan is coming to an end.

For comparison, a lithium-ion battery-powered calculator will likely last for a few months to 3 years, depending on the level of use, the calculator, and the battery type. 

Why Is a Solar-Powered Calculator’s Life Span So Long? 

As basic calculators only use a very small amount of energy, solar-powered, and dual-powered calculators can sustain use on just light energy for a very long time. 

For dual-powered calculators, they are able to significantly extend the battery life by recharging it or supplementing it, giving it a longer lifespan.

How Can You Tell If Your Calculator Is A True Solar-Powered Calculator? 

Do you have a calculator with solar cells and are wondering whether your calculator is a solar-powered, dual-powered, or battery powered? Here is a quick test to definitively see whether your calculator relies exclusively on solar power or has a back-up battery.

A true solar-powered calculator that does not have an additional battery will not work in the dark at all. To test your calculator, either attempt to use it in a pitch dark room or cover the solar cells and see if the numbers fade.

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A purely solar-powered calculator will not function in the dark, and when the solar cells are covered you will notice a fade in the screen as well as a significant delay after pushing a button. 

If your calculator continues to function in the dark, this is an indication that it is a dual-power or only battery-powered calculator. Unfortunately, without taking the solar cells apart, you will not be able to tell if it is a dual-power or only battery calculator. Fake solar cells can only be distinguished when taken apart.

Your Calculator’s Lifespan Depends On A Few Factors

The amount of daily usage:

The more you use your calculator, the shorter its lifespan will be on average. This is due to the fact that a battery’s lifetime is calculated in lifecycles. One complete lifecycle is when the battery is fully drained and fully recharged once. The more often this happens, the shorter the lifespan will be. 

How well you’ve maintained your calculator:

Maintaining your calculator well by charging it frequently, cleaning it, and taking proper care to not damage it, will help ensure you have the longest lifespan possible. See below for guidelines on how to properly maintain a solar-powered calculator.

How To Keep Your Solar-Powered Calculator Functioning Well For Long 

Maintaining your solar-powered calculator functioning well for an extended period of time is simple. Just like with all your devices, make sure to take good care and avoid physical damage to your calculator. 

Recharge your battery often: 

Make sure to recharge your battery often by placing your calculator in a well-lit spot. This will ensure your battery is fully charged and that your calculator is ready to be used when you need it. Avoid placing it in direct sunlight as prolonged exposure to intense levels of light can damage the solar cells.

Clean the solar cells: 

Clean the solar cells often to remove dirt, dust, and oil from your fingers. Wipe the solar cells clean with a piece of cloth or a paper towel. Any built-up dirt and grime can prevent sufficient light from reaching the solar cells.

Final Thoughts

A good, solar-powered calculator will not only make your life easier, but it will last you a long time so that you do not need to worry about frequent replacements. Expect your hand-held calculator to last you at least 5-10 years, and do not be surprised if it outlives its expected lifespan!

In general, if you have a solar-powered calculator you are likely to run into other issues before your battery dies. These issues include structural damage from falls or hits, keys sticking together, or numbers rubbing off from continued use.

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The technology of these powerful devices continues to amaze many, with solar cells becoming more and more common in everyday life. Keep an eye out for simple calculator-style solar cells in your products such as mobile phones, streetlights, Tamagotchis, and other toys!