Solar Panels House Melbourne

How Many Solar Panels Do I Need To Power A Refrigerator?

After installing a solar panel system at home, you may wonder whether using solar power instead of traditional electricity is more cost-effective. Since the electricity bill is a big part of your everyday cost, you are likely to know clearly where the money goes.

To keep food safe and consistently cool, refrigerators require access to a continuous power supply, so it may seem that solar power is not a viable option. However, with the right solar power configuration and power requirement calculations, you should be able to run any refrigerator with solar power.

Those looking to install a full off-grid solar power system often ask how much solar power they will need to generate to run basic household appliances. Even if you are just looking to offset some of your electricity costs with solar power, it is useful to know how much solar power you will need to generate to put a significant dent in your monthly electricity bills.

This is why we will explain how you can determine how much solar power you will need to run your refrigerator. After we have explained how you can calculate how much power you will need to power your refrigerator, you will then be able to calculate the power needs for all of your appliances and portable electronics.

So maybe there are questions in your mind about the power consumption of each appliance in your house. For example, how much solar power do I need to power a refrigerator? A refrigerator is necessary for all of you, so it is significant to figure out its energy consumption.

Calculating the Energy Requirements of Your Refrigerator

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Each electrical appliance will require a specific amount of power to run. As you would expect, the power requirements for a small coffee maker are significantly different from the energy needs of a full-size refrigerator.

While refrigerators have relatively large power requirements, it is worth noting that not all refrigerators will require the same amount of power. For example, older models tend to drain more power than the more energy-efficient newer models, while larger refrigerators will need more power than a smaller mini-fridge.

The first thing you need to figure out the wattage rating of your refrigerator. You can do this by finding the amps and the volts on the electrical label on the device. To find the watts, you multiply amps times volts.

Amps x Volts = Watts

You need to know its approximate starting wattage and the wattage required to run. The equation above will give you the watts required to run. Refrigerators require more power to start than they do to run. You can estimate the starting wattage by multiplying the watts by 1.5.

Example: refrigerater rated at 6.5A 110V = 715

Maximum Starting Watts: 1,073watts

The words "surge" or "starting load", or "starting watts" is used interchangeably.

As we know, different electrical appliance requires different amounts of power to start and operate. So using them can cost distinctive money. And charging bills is one of the most concerning issues for most solar power users.

One representative consumer of solar power is your refrigerator. Unlike lights, refrigerators can consume a large amount of energy to work, and the consumption varies according to how much food you put in and what kind of refrigerator you shop for.

The elementary thing is to calculate how much energy your refrigerator requires to work out how much solar power you need to run your refrigerator. And you can get this value with different methods.

  • Direct way: you may pay less attention to the given information, but almost all producers will attach the energy rating label on a sign. Normally, the sign will be posted on the door of the fridge.

Next, you need to know how many hours you want your appliance to run per day, and then you can get the final value by multiplying hours and the power.

This value will determine how large a refrigerator you will need and how many solar panels your solar system requires.

If you are usually absent at home, you can choose a small refrigerator and fewer solar panels. On the other hand, if you are always at home and cook a lot, you should buy a larger fridge and need more solar panels.

Running Watts

Another technique is to use the annual kWh usage of the refrigerator to determine the running watts. Most of the time, fridges will show their annual kWh energy consumption on the label. Or, if you search for your fridge model online, you should be able to find out the annual kWh energy consumption. For example, I found a fridge that uses 404 kWh per year. Divide that by 365 to get 1.11kwh per day. Next, divide by 24 and multiply by 1,000 to get the watts. So this fridge runs on about 46 running watts. 

Calculating Running Watts Once You Have the Power Rating

Once you have the annual kWh requirements of your refrigerator, you can determine the running watts, which will tell you how much energy your solar panels will need to generate each day in order to power the appliance. 

Once you have discovered your fridge's annual kWh energy consumption, you will simply divide that number by 365, as this is the number of days in the year. From there, you can divide that number by 24, which will give you the watts required per hour.

For example, if your refrigerator had an annual energy rating of 365kWh, it would require 1kWh per day. Once divided by the 24 hours in a day, you would have a running watts requirement of 0.042kW/h, as 1kWh ¸ 24 = 0.042. This means you would require a solar power system that could supply 42W per hour, as a kWh is equivalent to 1,000W.

The Solar Power Setup

A solar power setup suitable for refrigerator use requires several devices in addition to solar panels. First, batteries are needed to store the refrigerator's power at night or when clouds block the sun. A device called a charge controller will smooth the flow of power from the panels to the battery. The charge controller protects the battery from drastic fluctuations in power and ensures that it always receives the proper voltage and current. Lastly, an inverter will convert your battery's direct current (DC) power to the alternating current (AC) power used by the refrigerator.

Determining Your Solar Panel Requirements

Once you have the energy requirements for your refrigerator, as well as any other electronics you plan on running with solar power, you can begin assembling an appropriate solar array. Selecting solar panels is actually fairly straightforward, especially when you already know your energy requirements. This is because solar panels are usually sold according to the amount of energy they produce in watts. 

For this example, if you are using 404 kWh per year, that is 1.11 kWh per day. So you are going to need a total wattage of 300 combined solar panels. How did I come up with 300? You multiply the combined wattage of the solar panels by the number of hours of sunlight they will receive per day. A good rule of thumb is 4 hours. So 300 times 4 is 1200 watts. So 1200 watts divided by 1,000 equals 1.2 kWh produced per day.

How Many Solar Panels Do I Need to Power a Full-Sized Refrigerator?

You'll need to use the calculations above to determine exactly how many solar panels you'll need to power a full-sized fridge because panel output and refrigerator consumption vary. But to give you an idea of how many solar panels the average refrigerator will use, you can find out your kilowatt per hour consumption. 

You can determine your ref's daily consumption by using this formula: (Wattage × Hours Used Per Day) ÷ 1000 = Daily Kilowatt-hour (kWh)

Let's say your refrigerator uses 700 kWh per year, which is about 1.9 kWh per day. So if your solar panels produce about 1 kWh per day, then you'll need two solar panels to solar power your full-sized refrigerator.

An average ENERGY STAR rated (~19 cubic feet) refrigerator will take 2-3 solar panels to power. This is taking into account a 300W rated panel and an average 15-amp, 120V refrigerator.

Building Solar Panel Kits

For running a refrigerator all day, in addition to the 2-3 solar panels, a battery bank would need to add to store the energy produced.

Running a refrigerator off of solar power is not quite as easy as connecting it to a series of solar panels. Given the fact that refrigerators draw power 24 hours a day, it would be impossible to power one using only solar panels. In addition, solar panels only produce electricity when they are exposed to sunlight, so you will need to connect the panels to both a battery and an inverter to provide constant power to your refrigerator.

In simple terms, solar panels will generate electricity throughout the day. That power will be converted to AC power and stored in a battery bank, which will be able to supply power to the fridge after the sun has set.

How Long Will a Refrigerator Run on Solar Panels?

Depending on the number of solar panels you use to hook up to the fridge, your runtime is going to be affected by how much energy the refrigerator requires to stay cool.

Think about the need for a refrigerator to stay cool on a hot day versus a cool day. In hot weather, it requires more energy since it's being depleted from the heat.

Three factors that matter for refrigerator runtime

  1. Amount of solar power produced
  2. Battery storage (used when no sun is present)
  3. Power needs from the fridge

Let's use the refrigerator in my kitchen as an example. First, the specs:

  • 27 cubic feet 
  • 120V
  • 1.53 amps
  • 445W Defrost Heater, 145W Icemaker (we'll talk about these further down)

Factors to Consider When Sizing a Solar Set-up for a Refrigerator

There are other things to keep in mind when sizing how many solar panels you will need. Since people have different habits, these habits will affect the longevity of the fridge.

Let's review a few items that affect the power need:

  • Opening and closing a fridge door constantly will affect the power demands.
  • The amount of food inside will actually help stay cooler longer, given that the door remains closed and heat doesn't come in.
  • Whether the refrigerator has a freezer or not

Although figuring out how much solar power you need to run your refrigerator is not easy, the given analysis and calculations are practical and understandable. So you can just have a try. Work it out by the given ways and see how much money you will save when using solar power to operate your refrigerators.

While determining the power needs of your particular refrigerator may seem somewhat complicated, you must take the time to do the proper calculations. Running an appliance that you use daily off of pure solar energy is a beautiful feeling. Not only will you save money on your monthly electricity bill, but you will also know that you are making an environmentally friendly decision.

Frequently Asked Questions About Solar Panels

A 300-watt solar panel can run a small fridge. 300 watts is probably the minimum size needed to run a small to medium fridge, in combination with a 120Ah lithium iron phosphate battery and a 500-watt pure sine-wave inverter.

The average refrigerator and freezer use about 100 Wh per month. So a 100-watt panel receiving at least 8 hours of sunlight per day will produce almost 1 kilowatt-hour per day or 30 kWh per month. This means you'll need four 100 watt solar panels to keep that refrigerator running.

To keep food safe and consistently cool, refrigerators require access to a continuous power supply, so it may seem that solar power is not a viable option. However, with the right solar power configuration and power requirement calculations, you should be able to run any refrigerator with solar power.

Suppose you live in an area with high energy rates and a suitable solar rating and can afford the initial investment. In that case, it's worth installing solar panels in your home while the 26% tax break is in place — for the good of the environment and your wallet. But don't expect to eliminate your power bill overnight.

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