Changing solar panel efficiency in cloudy weather.
Also, the chart from the datasheet already takes into account that when the weather is overcast, the efficiency of the solar panel changes. If the relative efficiency drops by no more than 3%, the panels are considered good quality. High quality modules have a much smaller, and sometimes even positive, variation.
To calculate the relative change in solar panel efficiency in cloudy weather, use the formula:
(η 200 η 1000) / η 1000 = efficiency loss in %,
Accordingly for the previously selected sample:
(52 [ W ] /200 [ W/m² ] 265 [ W ] /1000 [ W/m² ] ) / 265 [ W ] /1000 [ W/m² ] =.1,8 %
The value was negative, which means that this solar panel is of high quality and even has a slightly higher efficiency in cloudy weather. Thus the panel efficiency when tested in good light = 16.19 %, and in cloudy weather (200 W) = 16.48 %.
For some solar panel models with PERC technology the gain in efficiency may even be more noticeable on overcast days.
Free kilowatts: How to choose a solar panel for your home?
If you live in one of the southern regions of Russia, solar panels can significantly reduce the cost of buying electricity. What to choose for trouble-free operation?
A good solar panel is an additional alternative energy source that allows to power several electrical appliances or even a whole heating system. But how to choose the right solar panel for a private home? We will tell you what are the solar panel and which one is more profitable to buy. Here’s also a ranking of solar panels for 2020.
Unfortunately, in Russia there is still no “green tariff”, which allows you to sell the state solar energy, so you can not make money on solar panels. But it is quite possible to save some money and have a “safety cushion” in case of power outage. For the full operation of solar panels in addition to the panels will need a battery, controller, inverter current converter, terminals and fasteners. Let’s start with the main thing with the panels.
How much does it cost to install a solar panel with a capacity of 1 kW?
For a solar panel system to work, you need to install the following devices:
- Solar panels themselves.
- Controller for battery charging.
- Batteries.
- The inverter converts the direct current from 12 V batteries to 220 V AC.
The average cost of 1 watt of panel power is 1 dollar or 90 euro cents. All in all, 1 kW of power will cost about 900 euros. Panels with 1 kW of power on a bright sunny day will bring about 8 kWh of energy (in winter and summer, as well as in cloudy and bright weather, the figures will be different).
The controller for a maximum current of 60 A will cost about 350 euros.
Ideally, a 100 Ah battery stores 1.2 kWh, but since they can not be discharged completely, but a maximum of 70%, we will take as accumulated charge, 840 W. As a result, to charge 8 kWh, we need at least two 250 Ah batteries (the rest of the energy will go to household consumers). They will cost about 700 euros (300 350 euros each).
Inverter for 1.4 kW, type Crown Micro Ricco 2.4K, will cost about 100 euros.
The bottom line is that 1 kW of power will cost us: (900 350 700 100) = 2050 euros. This is an average figure, since depending on the manufacturer and the technical parameters of the cost may vary.
Such a home solar power plant will save its owner about 2880 kWh per year, which at current rates is 2880 5.56 = 16012 (tariff for Moscow). As a result, the average payback of a solar home power plant with a capacity of 1 kW will be about 9 years.
Efficiency of solar panels in cloudy weather
Modern batteries successfully absorb not only the direct rays of the sun, but also scattered light, which is enough even in foggy weather. Therefore, the process of converting sunlight continues with cloudy. Of course, the efficiency of the battery will go down a little bit, but the digital indicator is not so critical. from 25% to 50%.
over, the effect of cloudiness on the solar panel can be unexpectedly positive.
First, the panels will generate energy from direct sunlight. And secondly, at the moment when the sun’s rays break between the clouds, the batteries, in addition to direct light, additionally receive light reflected from the clouds.
It turns out that on some cloudy days, the panels receive even more sunlight than on a fine day. Everything depends on the degree of “overcast”.
How solar panels work at night and on cloudy days
Many are driven by the desire to distance themselves from the general power grid and become independent. and save a lot of money on energy bills. The Russian government is developing a series of measures to promote alternative energy in our country. A bill is being prepared, according to which the surplus can be sold to state energy companies. Leading European countries have long pursued a competent policy in a new area for us and have already achieved some success. Residents of Germany, Sweden, Australia can not only use their own sources, but also sell.
The more rays hit the surface, the higher the efficiency. And if it’s not there? It turns out, and the panel does not work and no energy is generated. It’s not.
Efficiency in cloudy weather
In bad weather solar modules can produce electricity. It only depends on how dark it is outside. After all, the panel is able to absorb direct rays and diffuse light.
Obviously, the efficiency will go down, but not as dramatically as many people think. Depending on the degree of cloudiness on average it is reduced by 10-25%.
I want to mention a detail that must be taken into account when installing. The roof of the house, where it is planned to install a solar system, should not be in the shade. It is necessary to get rid of everything that gives this shadow: unnecessary trees, buildings, towers. Or move the installation to another location. This will give you more efficient operation of the entire mini power plant.
As for precipitation in the form of rain and snow, they somewhat reduce efficiency, but in general they do not affect the global performance. If it’s raining but sunny, the panels will steadily store energy. When using in winter, it is important to make a competent installation of the installation, to set the slope correctly (do not forget, in winter the sun is slightly lower than in summer), as well as to regularly clean out snow and ice.
Do the batteries work at night?
Clearly, there is no sun, which means the battery is not generating. The modules do not work at night. There are two ways to go here: either as soon as the battery goes into standby mode, you will have to connect to the public grid and take power from there. Or use batteries that can accumulate when it’s light and then give it back.
So, at night, in winter, any time there is not enough light to get enough power, you will be helped by batteries, where the stock of. The use of batteries is also viable in the case of permanent power outages.
Use in other countries
You won’t believe it, but Germany, for example, is a pretty cloudy country. However, it was there in 2006 opened the world’s largest fleet of power plants. Overcast, rainy weather prevails in many U.S. cities. This includes San Francisco, Seattle, and Boston. But solar power there continues to evolve and does not give up its position.
In addition, do not forget that in the field of solar energy is constantly evolving, improving technology, the modules are becoming more effective year by year, showing the best efficiency. And in addition, their cost is decreasing, which also affects the activity of the population to install and operate them.
Many scientists are engaged in the development of modules that will absorb even at night. There is still a lot of development and experimentation going on, but hopefully it will come on the market soon.
Which solar panels are better in cloudy weather
How much yield solar panels in cloudy weather or rain or snow.
A question that many people ask, but do not always get the right answer. The question is, what power I get from solar panels on cloudy weather. Today I will try to answer this question and show you in real numbers, not just words. So you can think about it and calculate. And also, in the future I will answer your second question, why do many people get zero power values, and not those that I have shown and voiced. It is strange that such information for so many years has not appeared on the Internet.
I immediately give to clarify that on overcast weather, all who have a complete system: controllers, inverters and so on, will receive about zero. And why it is so I will give an explanation in the future.
Today we are going to analyze how much power you can get in cloudy weather on systems with grid inverters. Why grids, it’s very simple. The efficiency of such systems is much higher than conventional systems with inverter. And our efficiency is measured in efficiency. That is, by installing solar panels with an efficiency of 16-24% and using a grid inverter, we get the total efficiency of the entire system Approximately 95% or higher. At a time when we use a system Solar panel, battery, inverter, battery charger, the efficiency could be around 70%. But we’ll talk about that in the future.
To date, grids have gained enough popularity and in most cases, many people buy such systems because of the price, and that does not need to use batteries.
But few thought that, besides price, these systems are also more efficient and easier to install. And modern grids, can also work with modern inverters, note only with pure sine. And besides that, the grid should be connected to the inverter only with a current sensor or a limiter.
In short, the installation of grid inverters has a high enough efficiency that even in cloudy weather can reduce the consumption of the house, in the presence of the state grid.
So, how much power you can get in cloudy weather, for example from a kilowatt of solar panels. In rain, snow or when there are heavy black clouds in the percentage, with a grid inverter.
Rain / snow we get the power of 5% (-4%) It all depends on the density of precipitation
Dense clouds without precipitation we can get up to 10% of the total capacity of the solar power plant (-5%)
As you can see everything is very simple. Knowing this you can already roughly understand what power you can get when there is no sun.
And maybe you can estimate how many panels can be added to get your required minimum in cloudy weather.
By testing the grids and seeing how they work at the same time, I was able to draw this conclusion. But since to be sure of these data it is necessary to test not just one but at least two devices simultaneously and not on the same system, therefore I did not publish these data openly.
Also the operation time in cloudy weather increases, due to the fact that the light is scattered. Instead of 5 hours in the spring the run time increases to about 8 hours and sometimes more, depending on the length of the sunny day.
How effective are solar panels in winter and in cloudy weather
A solar panel can be a spectacular home decoration and a profitable source of electricity. But many people are concerned. will the design be effective in winter and in bad weather, when there is little sunlight?
Operation of solar panels and controllers in cloudy weather
In this article I have described only my personal experience and actual instrument readings that I have recorded on my wind-solar power plant. There is no theory or assumptions here, only real numbers and data. The solar panels also work on cloudy days, in all light conditions, even with heavy clouds the solar panels still produce power. But this energy is sometimes so small that some controllers simply do not work and write that there is no charge. So a lot depends on the controllers.
I have a small array of solar panels consisting of four 100 watt panels, the total power of the batteries is 400 watts. But the truth is that the power is not even in bright sunshine. On cloudy days this array can give from zero to 3A of charging current, mostly 1.5A if the sky is thickly covered with clouds. But there are very cloudy days when the charge is almost zero and the charging current is only 0.2-0.4A, and that’s from a 400 watt array.
On one cloudy day I made a video of the solar panels starting in the early morning. The main goal was to show how two types of controllers work, one PWM controller (Solar30) and the other MPPT controller (Photon 100 50). But you can also clearly see what the solar panels themselves give at this low light. On this day, the charging current reached 1.6A during the day, and as a result, the array of solar panels gave only 66 watts of energy during the daylight hours. Below is a video of testing controllers and solar panels.
I think the video and everything is clear, here’s how the solar panels on the most cloudy days in winter, and the energy output is very low, we can say that this energy is simply not, because 66 watts per day with an array of 400-watt batteries is very little. But overcast days are different and then the output is much higher, but in the sun even in winter, such an array of batteries generates an average of 1.5 kW of energy per day. In summer twice as much, but because the battery capacity is not much, part of the energy from the sun is not used, there is nowhere to store it.
As a result, in place with a 300-watt wind turbine generator, which in winter often gives more energy than the solar panels, the total production of energy exceeds the consumption of energy, and I consume about 20 kW per month.
What to look for when choosing a solar panel
Due to the fact that the use of solar energy for household purposes has not yet become commonplace, and the choice of solar panels causes certain difficulties, we offer a list of the most important parameters. So, when buying such a module, you should pay attention to the following points:
Think solar panels will not work in a cold, cloudy climate ? | Sustainable Energy
It is important to pay attention to how long the manufacturer is present on the market and what its production volume is. The longer the manufacturer has been in the industry, the more it can be trusted.
For what purposes the energy obtained will be used: for charging small appliances, for power supply of large electrical appliances, for lighting, or for a full-fledged power supply of the house. It is from the purposes for which you buy a solar module, depends on the choice of output voltage and power panels.
For small electrical appliances enough 9 V, for charging smartphones and laptops. 12-19 V, and to provide the entire power system of the house. 24 V or more.
SOLAR PANEL CLOUDY DAY OUTPUT: Best Solar Panels for Cloudy Days
This parameter is calculated based on the average daily power consumption (the sum of the energy consumed by all appliances for the day). The capacity of the solar panels should with some reserve overlap consumption.
Solar Panel Energy Comparison. Sunny vs Cloudy Day | Ludicrous Feed | Tesla Tom
There are 4 quality categories of photovoltaic cells that make up a solar panel: Grad A, Grad B, Grad C, Grad D. Naturally the first category is best, Grad A. Modules of this quality category have no chips and microcracks, are uniform in color and structure, have the highest efficiency and are practically not subject to degradation.
The service life of solar panels varies from 10 to 20 years. Of course, the duration of full performance of such a power system depends on the quality of batteries and their proper installation.
The most important are efficiency, tolerance (permissible deviation in power), temperature coefficient (influence of temperature on battery performance).
Having understood the main technical characteristics, we offer you a rating of the best solar panels in 2022.
