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The Sun Behind the Clouds: Can Solar Generators Keep the Power On During Cloudy Days?

Solar panels can be very useful in generating power, saving you money, and helping the planet. However, they aren’t feasible for everyone. Many articles discuss solar panels working best in full sun, but what about days when it is cloudy, partially cloudy, or dark and stormy?

While they can work on these days and still produce a good amount of power, you won’t get the same energy production you would get on a full sun day.

Solar generators work on cloudy days, though not as efficiently as on sunny days. The photons in sunlight can penetrate through clouds, so the generator can still produce some power.

However, because there is less sunlight, the generator will not produce as much power as it would on a sunny day. Before we answer more of your questions related to solar generators on cloudy days, at night, and in some other situations when the sun is not smiling, let us first understand what are the components that make up a solar generator.

What Components Make Up a Solar Generator?

A solar generator is a compact device that contains the four main components of solar power systems: a solar panel system(usually sold separately), batteries, a charge controller, and an inverter.

A solar panel system is a set of solar panels that are used to capture solar energy and convert it into electricity. Solar panels comprise several smaller units called solar cells, which are connected. 

When sunlight hits a solar cell, it causes an electrical reaction that generates a flow of electrons. This flow of electrons is then harnessed to create an electrical current, which can power electrical devices. 

Montek Solar Generator

The battery or batteries store electricity when the sun is not shining. While a charge controller is used to regulate the flow of electricity in the solar system from the solar panels to the batteries. 

Inverters convert the direct current (DC) power produced by the solar panels into alternating current (AC )power that can run appliances and electrical devices. Solar generators would be limited to powering DC devices without an inverter. 

Will I Get Power on Cloudy Days?

Solar panels can work on cloudy days and still produce a fair amount of power. However, they don’t work perfectly and can produce less power than you are expecting or used to.

They aren’t as efficient when your solar panels are blocked from getting full sun, either by clouds or shade. You can lose a lot of power or have far less for the day than you might expect. For that living off-grid, this can be pretty bad as you may have much less power than expected.

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How Do Solar Panels Work in Cloudy or Rainy Weather?

On cloudy and rainy days, it’s not the generator that’s directly affected when the cloud cover appears, but the solar panel. Solar panels need light from the sun to generate power.

When heavy clouds appear, heat or the photons in sunlight can penetrate through the clouds, so the solar panel can still collect some range of power. However, because there is less sunlight, the solar panel output will not be as much as it would on a sunny day, so they are less effective when it’s cloudy or raining. 

The most important factor for the popularity of solar panels is not the amount of sunlight a city sees, but rather the cost of electricity. Many of the top cities for solar in the U.S. are not particularly sunny, but have high electricity rates, resulting in homeowners seeing major benefits in terms of bill savings and a quick break-even point.

How Much Power Can I Still Get on Cloudy Days?

You can lose a percentage of your efficiency depending on how dark the sky is due to clouds. On average, you can expect to lose anywhere between 10% and 25% of your efficiency when it is cloudy out. This can be a huge disadvantage, especially when solar panels are already not super efficient.

However, if you live in a very cloudy area, like Washington state or the UK, you don’t have to go without solar panels and stick to grid systems. Many solar systems are now improving their efficiency.

While they still lose a large amount of power when it is cloudy, they are already starting off more efficiently, so it isn’t as damaging to your power draw and you still have the ability to produce enough power to pay off your system.

Additionally, while this 10% to 25% seems bad, it isn’t actually all that horrible. You lose about the same amount of power when it is particularly hot, or above 77 degrees Fahrenheit [25 degrees Celsius], so cloudy days and hot days work about the same on your solar system.

How Do I Offset Loss of Power From Cloudy Days?

One of the best ways to deal with cloudy days is to get a battery bank for your solar system. This allows you to take advantage of sunny days by filling up your batteries, while also giving you power at night and on cloudy days when you need a bit of a boost.

During sunny days, or just times when you aren’t using a lot of power [including cloudy days when you aren’t home or just don’t need power], your excess power will go to your battery bank to be saved for later.

While battery banks can be expensive, they actually save you a lot of money in the long run as you don’t have to waste any of the solar energy your system produces. They are necessary whenever you are looking at going off-grid and not relying on any other power, but they can also be helpful when you are connected to the grid and still want to use most or all of your solar power.