How Many Solar Panels do I Need for a Solar Array?

Installing a solar array at your residence or office is a wise investment that will save you on long-term energy costs while reducing your carbon footprint. However, this sophisticated system will require some considerations, with determining the number of solar panels among them. Here’s what you’ll need to factor in. 

What are the types of solar panels?

There are three main types of solar panels that you will consider when selecting, with different pros and cons, as well as lifespans:

  1. Monocrystalline solar panels

These solar panels are made from cells of silicon wafers assembled into rows and columns to form the rectangular panel, with a glass sheet covered. Monocrystalline panels are cut from a single, pure crystal of silicon. 

  1. Polycrystalline solar panels

Like the monocrystalline solar panels, polycrystalline panels are made from silicon wafers, however, they are composed of fragments of silicon crystals which have been melted together before being cut into wafers. 

  1. Thin-film solar panels

These panels are made from a mixture of materials, with the most prevalent material cadmium telluride (CdTe), amorphous silicon (a-Si) or copper indium gallium selenide (CIGS). This substance is placed between transparent conducting layers for capturing sunlight, and a glass layer for protection. 

How much sun exposure will your solar panels receive? 

Once you’ve worked out which solar panel types you’ll be installing, you’ll need to work out how much sunlight your roof gets in an average day to determine how many panels are needed. Elements that impact the amount of sun exposure will include the direction your roof faces, any shading such as trees or tall buildings and your geographic location.

How much energy do you use?

Another important factor that determines solar panel numbers is deciding how much energy you use on a daily basis. One way of doing this is to check your energy consumption over the past year, but it’s also important to determine which appliances are being used daily because certain appliances use electricity more than others. Here are some of the top contenders for electricity use:

  • Heating and cooling systems
  • Kettles and cooking appliances
  • Geysers 
  • Refrigerators and freezers
  • De-humidifiers

What is solar panel string sizing?

The solar panel string is the number of solar panels that are wired into a power inverter. Your string sizing will calculate how many panels you’ll connect to an inverter for optimal efficiency. Depending on your energy requirements, you might need more than one inverter, however, this is usually the case for commercial applications and depends on whether you have a grid-tied solar system or are going off the grid. 

Why does string sizing matter?

It’s important to determine the string size, because inverters have to operate within a specific input voltage range so it’s vital that your panel strings’ output is within range. If the panels can supply sufficient voltage, then the inverter won’t have enough power to switch on and function. To optimise energy output, you want a narrow voltage range referred to as the maximum power point range (MPP) range whereby the inverter runs at peak efficiency. 

Calculating a solar panel estimate

If you’re looking for a ballpark figure to determine the number of solar panels, then you will take your average daily electricity usage (KWh), divided by your monthly peak sun hours and multiply by a factor of 1.15. This should give you the average DC solar power. Divided by the size panel you want to use and you get the number of panels required to power your home. You will then have to factor in what inverter is required for this particular string sizing.  

To give you a rough idea, our home uses about 30 000KWh and it will require 17 solar panels under ideal conditions. We still have to ensure that the inverter is sized correctly to take the inrush current sin account.

What about the inverter?

The inverter will connect to the solar panels to convert the direct current (DC) power into alternating current (AC) power. DC power is ideal for solar panels as it absorbs the sunlight and moves in one direction, but your household appliances require AC energy. There are two main types of inverters:

  1. Pure sine wave inverters

These solar inverters provide a pure form of power that allow devices to operate without distortion and disturbance. They’re important for critical equipment such as computers. These are typically the best choice for solar systems. 

  1. Modified sine wave inverters

These have higher efficiencies and run at a lower cost, but they aren’t ideal for all applications such as laser printers, television sets or fluorescent lights. 

There are a lot of factors that need to be considered when installing an effective solar array which is why it’s best to consult with industry experts, JUP Solutions. They will accurately determine the number of solar panels required to fit your inverter, so that all your power needs are met and you enjoy all the benefits of solar power

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