How to Do Solar Panel Calculations? (Complete Guide)

How to Do Solar Panel Calculations? (Complete Guide)

Are you considering installing solar panels in your home? Taking advantage of solar energy can save you money and reduce your carbon footprint. But before committing to an installation, you need to know some crucial solar panel calculations, including size, number and out, to maximize the efficiency of your installation and ensure that you make a wise investment. This guide will provide all information about solar panel calculations you need to know, as well as the maintenance of solar panels and two popular solar panels you can purchase.

What Is a Solar Panel?

A solar panel is a photovoltaic (PV) module that converts sunlight into direct current (DC) energy. This energy then flows into an inverter, converting it into alternating current (AC) energy that can be used to power homes, businesses, and even entire cities. Solar panels rely on the sun's energy, making them an incredibly sustainable and eco-friendly energy option.

Calculation About Solar Panel

To make the most use of solar panels, here are some calculations to consider before you invest in them:

Solar Panel Size

To calculate the solar panel size for your home, start by determining your average daily energy consumption in kilowatt-hours (kWh) based on your electricity bills. Then calculate your daily energy production requirement by dividing your average daily energy consumption by the system efficiency.

Next, consider the amount of sunlight available in your location, as areas with more sunlight require fewer panels. Determine the solar panel capacity by dividing the daily energy production requirement by the average daily sunlight hours.

Account for panel derating to factor in efficiency losses. Divide the actual solar panel capacity by the capacity of a single panel to determine the number of panels needed.

For example, if your average daily energy consumption is 30 kWh and the system efficiency is 80%, and you have an average of 5 hours of sunlight per day, you would calculate your daily energy production requirement as follows:

Daily Energy Production Requirement = 30 kWh / 0.8 = 37.5 kWh

Assuming a derating factor of 85%, the solar panel capacity needed would be:

Solar Panel Capacity = 37.5 kWh / 5 hours = 7.5 kW

Considering the derating factor, the actual solar panel capacity would be:

Actual Solar Panel Capacity = 7.5 kW / 0.85 = 8.82 kW

If the capacity of a single solar panel is 300 W, the number of panels required would be:

Number of Panels = 8.82 kW / 0.3 kW = 29.4 panels

It's important to consult a professional installer to validate these calculations and assess your specific requirements.

Solar Panel Output

Before installing solar panels, it is also crucial to calculate their output to ensure optimal performance. Usually, solar panels generate energy ranging from 250 watts to 400 watts per hour. But their actual output is influenced by a variety of variables, such as their efficiency, orientation, and location. Suppose there is an energy loss of 25%, then you can get the formula:

Daily watt hours = Average hours of sunlight × solar panel watts × 75%

The following is an example:

If you reside in an area that receives 5 hours of maximum sunlight and your solar panel has a rating of 200 watts, the output of your solar panel can be calculated as follows:

Daily watt hours = 5 × 200 × 0.75 = 750Wh

That means a solar panel that has a capacity of 200 watts can produce approximately 750 watt-hours.

Solar Panel Efficiency

The efficiency of a solar panel refers to the amount of sunlight that is converted into usable energy. Panels with higher efficiency are able to generate more power from the same amount of sunlight. Therefore, it’s vital to consider the solar panel efficiency. Below is the formula to calculate it:

Efficiency (%) = [(Pmax ÷ Area) ÷ 1000] × 100%

In this formula, the Pmax stands for the maximum solar panel power; the Area equals the width times the length of solar panels; 1000 is the conversion factor that transforms power output per unit area from watts per square meter to percent.

For instance, assuming a solar panel has a surface area of 1.6 square meters and the highest power output of 200W, then its efficiency would be:

Efficiency = [(200 ÷ 1.6) ÷ 1000] × 100% = 12.5%

Thus, the efficiency of this solar panel is 12.5%, meaning that it can convert 12.5% of sunlight into usable energy.

Advantages of Solar Panels

Solar panels present a cost-effective option for both homeowners and those who enjoy the great outdoors. The advantages of using solar panels for charging your appliances are as follows:

Cost savings

By eliminating your dependence on traditional power sources, you can save a significant amount of money on your monthly utility bills.

Eco-friendly energy

Solar panels utilize the sun's energy to produce electricity without emitting harmful gases. As a result, they help decrease carbon footprint and reduce environmental pollution.


Unlike traditional electrical systems that rely heavily on fossil fuels, solar panels use renewable energy from the sun. This eliminates the need for highly flammable materials, making it a much safer option.

Low maintenance

Once installed, solar panels require minimal upkeep, thanks to the fact that there are no moving parts to wear out or require regular lubrication or repair.

How to Maintain Your Solar Panel

With proper maintenance, solar panels can generate efficient electricity for many years. To maintain and improve the efficiency of solar panels, there are some tips you need to know:

Clean solar panels regularly

The gathering of debris, dust, or foreign objects on the panels’ surface can hinder sun absorption efficiency. Frequent and thorough cleaning is necessary to maintain the effective conversion of solar energy to electrical energy.

Keep solar panels free of shade

If you keep solar panels shaded and prevent them from absorbing sunlight, their ability to produce energy will be reduced. To optimize energy production, it is important to ensure that solar panels are in direct sunlight and not in the shade.

Inspect your solar panels after extreme weather events

A severe storm, tornado, or hurricane can cause damage to solar panels, affecting their performance. You can easily detect issues by inspecting their appearance or monitoring their performance online.

Top Portable Solar Panels

Anker solar panels have greater efficiency in comparison to other conventional panels, allowing the conversion of more sunlight into usable electricity. In this part, we’ll recommend two popular Anker solar panels.

Anker 625 Solar Panel

The Anker 625 Solar Panel uses high-grade monocrystalline material to assure exceptional efficiency and endurance. With its powerful sunlight-absorbing surface, its conversion efficiency can go up to as much as 23%. Designed to work with Anker PowerHouse 521, 535, and 757, this 100W solar panel is ideal for outdoor activities such as camping and road trips, providing ample electricity to meet your needs.

Furthermore, this lightweight and compact solar panel features two charging ports to allow simultaneous charging of two devices. Also, the Suncast technology ensures that the panels are accurately positioned to enhance solar charging for remarkable energy efficiency.

Anker 531 Solar Panel

Similarly, with a high energy conversion efficiency of 23%, the Anker 531 Solar Panel is also a good choice to power your essential appliances, such as a coffee maker or mini fridge. Also, equipped with a flexible kickstand, it enables three-mode angle adjustments. You can effortlessly modify the panel angle to 40°, 50°, or 60° to maximize solar power.

Additionally, the solar panel has IP67 waterproof protection preventing it from getting damaged from harsh weather and complementing an adventurous lifestyle. Furthermore, it provides protection against short-circuit and over-voltage, ensuring the safety of you and your devices.


All in all, the solar panel calculation is not as daunting a task as it may seem. With the help of our simple guide, you now know how to calculate the exact amount of power your system needs and choose a correctly-sized setup that will meet your requirements. Even better, you can easily find reliable and cost-effective products, such as Anker solar panels, and have them installed in no time! So if you're ready to start taking advantage of one of nature's most abundant renewable resources, installing solar panels is definitely the way to go. 


How to decrease your energy usage?

Here are some simple ways to decrease your energy usage:

  1. Install LED lights.
  2. Turn down your thermostat.
  3. Unplug appliances when they’re not in use.
  4. Reduce water consumption, such as by taking shorter showers.
  5. Invest in a solar power systemand use renewable and cost-free solar energy to charge your electronic devices.

How to maximize the utilization of solar panels?

Below are some tips for maximizing the utilization of solar panels:

  1. Modify your energy usage. For example, perform energy-consuming tasks like laundry during the morning or afternoon when your solar panels get enough sunlight.
  2. Install a solar battery to have a reserve power source at night or on overcast days.
  3. Arrange the usage of various appliances at different times to optimize and stabilize the usage of the available solar energy during the whole day.
  4. Insulate your home to avoid air leaks. Thus, your HVAC will require less energy, freeing more solar energy for other household tasks.
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