A Guide on How to Calculate Solar Panels Output

Solar power is an investment, and the goal is to ensure you get the most out of it. Various factors affect the output of your solar panels. They range from panel size, efficiency, and orientation. It is essential to calculate solar panels output before installing them on your roof or the ground.

Generally, panels will range between 250 and 400 Watts.  Exactly how you can calculate your solar photovoltaic array depends on various variables. In this article, we are going to look at how you can achieve this.

How to Calculate Solar Panels Output

Some of the essential factors that you to look at when calculating the output are:

  • The efficiency of your solar panels
  • Your location
  • The orientation of your solar panels

Other variables exist that can directly change the outcome. However, these are the primary ones.

Determine the Standard Test Conditions

You can start by looking at the parameters that determine solar panels’ wattage rating. As stated earlier, the wattage is usually between 250 watts and 400 watts. However, it does not mean that your PVs will be generating that much energy at all times. The efficiency number is an estimated range of the expected output when all conditions are perfect.

These perfect conditions are known as Standard Test Conditions (STC) and are determined in a laboratory after tests for the solar panels. Standard Test Conditions for PV modules are 77 degrees Fahrenheit and 1000 watts of sunlight per square mile.

If you achieve these perfect conditions, a panel of a 250-watt rating will generate exactly 250 watts of electricity. Those are laboratory tests. How well the modules perform in the real world depends on:

The Efficiency of Solar Panels

Wattage informs you of the amount of electricity your solar panels can produce, while efficiency tells you how much sunlight your panels can convert into electricity.

A quick example: if your solar panel’s efficiency is 15%, it means that it can convert 15% of sunlight passing through the PV modules. Various factors affect efficiency. Solar cells within the panels can vary their efficiency depending on how reflective they are. If the cells are less reflective, they will collect more sunlight instead of bouncing it back to space.

The surface surrounding the rooftop can also affect efficiency. The most common factors here include:

  • If there is shade from buildings or nearby trees: You should avoid shading at all costs. You can do so by trimming trees and installing panels properly to prevent shading from buildings nearby.
  • Presence of a lot of dirt, pollution, and dust: These are harmful factors that can contribute to the degradation of solar panels over time. You can hire professionals to clean your panels regularly.
  • A thick cloud cover: This is a natural occurrence, and there is no much you can do about it. However, it is good to know that solar panels can still produce electricity even on cloudy days or intervals.
  • Availability of snow.

How Orientation and Location Affect Solar Output

Your location determines the amount of electricity the solar panels can harness. Historically, solar was first adopted in sunny states in the southwest.

As solar panels get exposure to more sunlight, their production increase– the more the sun, the better. However, even the northern parts can still benefit from solar power.

The direction that your solar panels face also affects the output. If your panels face the direction that receives more sunlight, they can capitalize on this and give out more energy. The recommended orientation for solar installation can be south or west, depending on your location. Differences in your available physical space and surrounding conditions can also affect this decision.

Solar Output Calculations

Let’s get into some mathematical formulas. The simple formula for calculating solar panel output is:

Average hours of sunlight × solar panel watts x 75% = daily watt-hours

First, 75% accounts for all the above variables. Now, let’s look at an example.

Suppose you live in a place that experiences about 5 hours of sunlight on average, and your panel has a 290-watt rating. You will calculate the solar panels output as follows:

5 hours x 290 watts x 0.75 = 1,087.5 daily watt-hours

If you want to translate it into more familiar terms that you see on your energy utility bill, divide the figure by 1000.

That will be 1.0875 kilowatt-hours per solar panel.

Calculating solar panels output does not have to be daunting when switching to solar. You can look for reputable solar calculators to help you with the process. Most companies will also assist you when you consult them about this. Remember, solar panels’ efficiency can also affect your solar energy production.

At Dynamic SLR, we offer a free solar quote to help you estimate the total cost of solar installation. You can get in touch with us today, and we help you transition from conventional electricity to solar energy. We have quality products and reliable services in Texas.