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How Many Solar Panels And Batteries Do I Need?

Are you presently considering adding a solar system to your home? With several homeowners in the UK using solar now, many more are realizing the numerous benefits they stand to derive by getting one. Therefore, if you’re thinking about adding the system to your home but do not know where to start, you’ve come to the right place.

Here, we’ll help you calculate the number of solar panels and batteries you’ll need to power your home. Starting from the panels, you can begin by taken into account everything that makes use of power in your home to get a good idea of how many you’ll need.

• Firstly, you’ll have to determine the number of watts you use. Simply go through your utility bill for kilowatt-hours (kWh). This varies amongst homes and being able to identify your daily average energy usage will assist you in getting your solar needs.

• Secondly, you have to determine the peak sunlight hours - having in mind that the solar panels only work when under direct sunlight. Once determined, you can then multiply the figure in hours by your home’s hourly energy usage and divide by your selected solar panel’s wattage.

Generally for a 1500 square foot house, you might need around 15 to 18 solar panels to cover the house’s electricity.

Meanwhile for batteries, there are also some factors to be considered to determine the number of batteries you’ll need for your house. These factors include your home’s power or electricity usage, the period of time in which the battery will be used as well as the battery’ specifications. Once done, you’ll be able to calculate the number of batteries required by your home.

If your solar panels are mounted on your roof and you require a ladder to reach them we would always recommend you get a professional to do the work for your own safety.

The importance of selecting the right size battery for your home simply cannot be overemphasized. A lot of home and property owners are facing this challenge and understandably so. Selecting the right battery size for your needs depend on a number of factors which includes your motive for adding a battery, your electricity usage, your budget as well as your panel array size, be it new or existing. In this post, we’re going to take you through some of these factors to help you determine the right battery size for your home or property. Let’s take a look!

• Your motive for getting a battery. While most people purchase a battery to wipe out their need to purchase electricity from the grid with the hope of making some savings, others add a battery so as to enjoy backup power. There are also some who just needs it to power their home with solar energy. It’ll not be economical to size a battery to effectively take you off the grid, but if your motive is to make savings, then you’ll should expect to purchase some electricity from the grid during the year.
• Electricity usage. The average household uses about 16kWh of electricity on a daily basis. During the daylight hours, most of these household will use a third of their electricity when the solar panels are still generating electricity, while the remaining two third are purchased from the grid. In other words, you’ll require a minimum of 10kWh battery capacity if you were to use a battery to power the electricity you purchase from the grid.

For a typical British household, you’ll most likely need a 5kWh solar power system which normally generates about 17 to 21 kWh on a daily basis depending on your location in the UK.

How much energy a solar panel produces depends on its manufacturer and exposure to the sun. A good-quality solar panel typically has a power output of about 300 watts per hour, but this can vary from about 240 to 360 watts. How much energy your solar panel will produce per day depends on how many hours of unshaded daylight it’s exposed to.

Here’s an idea of how much energy you could expect a large commercial solar panel installation to produce in a year.

Solar panel system size, No. of solar panels, Annual electricity output

11kW, 44, 9,350kW

20kW, 80, 17,000kW

30kW, 120, 25,500kW

40kW, 160, 34,000kW

50kW, 200, 42,500kW

It’s vital to purchase a solar panel system that suits your property. If you’re investing in a solar panel system, it makes the most financial sense to get the biggest one possible. However, whether you can do this or not depends on budget and space.

Here’s an idea of how much roof or ground space you’ll need to install a few different sizes of commercial solar panel system.

Solar panel system size, No. of solar panels, Approximate area required

11kW, 44, 64m²

20kW, 80, 116m²

30kW, 120, 173m²

40kW, 160, 231m²

50kW, 200, 288m²

One of the things that has been on the UK government’s agenda for some time now is to promote the use of renewable energy sources. In fact, the Renewable Energy Directive put out by the EU instructs all member countries to achieve a 20 percent renewable target before the year 2020. The UK’s commitment to this objective has been made quite glaring with a number of funding options that has been put in place to help business owners looking to solar panels on their properties. This commitment was also showcased by a reduction in the cost of solar panels, so new investors have little to worry about. Although there aren’t any grants in the conventional sense, but there are opportunities for solar panel funding in the UK. At present, the only scheme open to new applications is the SEG - Smart Export Guarantee which came into effect on 1st January, 2020.

In general, there are four notable incentives in the UK for solar panels which includes the aforementioned Smart Export Guarantee, Reduced VAT on Energy Saving Products, Feed-in Tariff ( no longer open to new applications ), as well as the Renewable Heat Incentive ( RHI - applies only to solar water heating ).

Being the only one still open to new applications, we’ll provide you with some insights on SEG. The Smart Export Guarantee allows small scale low-carbon electricity generators to receive payments for surplus energy they’re able to export back to the grid. Although, this is not a direct government scheme, all licensed suppliers are necessitated to offer an export tariff to their customers. Those suppliers with more than 150,000 customers are obligated to offer a tariff, while the suppliers with fewer customers can partake on a voluntary basis.

Yes – solar panels do work in winter. Contrary to popular belief, solar panels can still work under daylight, even if it's not hot. Of course, they won’t generate as much electricity as they would during the summer months, as the days are shorter, but they will still generate electricity during those daylight hours.

Once you know how solar panels work, it’s easy to understand why solar panels work in the winter. Solar panels are made up of photovoltaic (PV) cells, which are units usually made out of silicon. These cells contain electrons that create energy when light hits them. The cell can then convert this energy into usable electric current and into your system to be used around the home.

Although it might seem strange, solar PV cells can actually work better when it’s cold. Too much heat around the cell can cause it to be inefficient, due to the difference in energy between the energy from the sunlight and the electrons in the solar cell. During cold weather, the difference between them is higher, so more

The higher the energy difference between the two sets of energy sources, the more power that the cell can produce when it’s struck by light. Of course, the downside is that there are fewer daylight hours in the winter, so you’ll still see a drop in energy production – but at least you know that your solar panels are still working efficiently. The other thing to bear in mind is that obstructions like snow and lots of cloud cover will impact the amount of electricity your solar panels will produce. Luckily the UK doesn’t get too much heavy snow, so any snow that does settle on the panels will melt quickly. As for cloud cover, even on exceptionally cloudy days your panels will still generate some electricity – just not as much as they would on a clear day.