Do Solar Panels Charge On Cloudy Days

Solar energy produced from a solar panel is determined by how many photons from the sun strike the solar cell, and how many of these photons actually get an electron moving to create a current. This is how a charge from a solar panel is produced.

On cloudy cover days, with rain, humidity, air pollution, or dust in the atmosphere, much of the solar radiation is scattered, meaning the energy that comes from the sun goes in different directions. We call this diffuse radiation, solar energy but its rate is smaller. This is opposite to direction radiation which is when the sun’s energy comes in a beam of straight rays without interference like on a clear dry day with no dust and humidity.  

How Photons behave as they pass through the atmosphere

Solar panels will charge during the day even when it’s cloudy because there is some light hitting them. However, the efficiency is greatly reduced.  On a cloudless day solar panels should be producing about 30% more energy than on a cloudy day since the sun is much brighter and so can reach them better

What you can do to get more power

Unless you are in a storm cloudy weather should come and go. But they are some things you can do to get more out of your solar system.

Size your system appropriately

Your solar panel system will provide output according to the peak sun hours. The term “peak sun hours” refers to the solar insolation which a particular location would receive if the sun were shining at its maximum value for a certain number of hours.

The output of a solar panel is usually stated in watts, and the wattage is determined by multiplying the rated voltage by the rated amperage. The formula for wattage is VOLTS times AMPS equals WATTS. So for example, a Solar panel rated 18V providing 3 amps will be rated 54 watts (60 watts in most cases)

V x A = W
18 volts times 3 amps equal 54 watts

If an average of 6 hours of peak sun per day is available in an area, then the above solar panel can produce an average of 300 watt-hours of power per day; 54w times 6 hrs. = 360 watt-hours.

For you to get the same output in less favorable conditions you may need to add other panels to the system or get a panel rated higher.

Use High Efficient Solar Panels

You can find three different types of solar panels in the market. Polycrystalline, monocrystalline, and Thin-film Solar panels.  Monocrystalline solar panels have the highest efficiency among the three.  The new ones can reach up to 23% efficiency.  They will perform better in cloudy conditions than similarly rated polycrystalline and thin film solar panels.

However, some devices like a 5-watt Solar trickle charger for a car battery will continue to work effectively as they do not require much sunlight.

Wiring Panels in Series or Parallel

You wire solar panels in series or parallel to increase voltage and amperage. Wiring solar panels in series will add up the voltage while wiring them in parallel will add up the amps. You can also wire them both in series and parallel which will increase both volts and amps.

Wiring Solar panels

Use an MPPT Charge controller

Because the MPPT controller is always tracking the maximum power point it can react quickly to changes in the input Voltage. This includes when there are passing clouds that can read to a drop in voltage. 

Use a Battery bank

A battery bank will help you get the power you need when the grid goes down or during tough weather conditions. Battery banks are also great for storing solar energy so that they can be used at night, on cloudy days, or while on vacation in your off-grid cabin.  

Solar Panels Work Best in Clear Skies
  1. Do Solar panels work in the rain?

    Solar panels are typically made of two or more layers of crystalline silicon wafer cells which have been chopped to allow better light transmission. The cells bring in energy during the day in either clear sky conditions or with low-hanging clouds. When exposed to raindrops (or any other type of liquid), they lose efficiency because they block out sunlight penetration–in addition to causing puddles near the panel that can cause mineral buildup over time. That being said, solar panels can still produce electricity under cloudy skies although production is diminished.

  2. Can Solar Panels Work in the Winter?

    Yes, solar panels can work in the winter. Actually they can even work better in the winter in clear sky conditions. This is because high temperatures can also cause solar panels to lose efficiency. But cloudy conditions and snow will hamper the solar panels performance and it is best practice to use the panels while tilted in order for the snow to fall. You may also need to be clearing the snow yourself.

  3. Do solar panels work in the shade ?b

    Ideally no, but sometimes it depends on the shape of the panels. Manufacturers have to design them to get as much direct sunlight as possible in order for a solar array to work. Even when they are working, they produce less electricity than if there was direct access to sunlight, so shading will cut down on efficiency considerably.

    If you plan on installing solar panels, it's best if you can install them in an area that has mostly clear skies at least 9 months out of the year rather than across any border with shady areas that may be too dense or thick to let light through. If you do decide to go for a solar power installation and plan is residential, check your zoning laws first before proceeding so you don't risk getting

  4. Can you use Solar Panels at night?

    No, you can't. Solar panels require sunlight in order to work. But they would react to any form of visible or UV light but it won't be sufficient to produce a meaningful charge. The best option in order to use a solar panel system at night is to use a battery bank that stores the excess energy produced during the day so that you can use it at night.


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