A Homeowner’s Complete Guide for Choosing Generator Sizing for an Off-Grid Solar System

A Homeowner’s Complete Guide for Choosing Generator Sizing for an Off-Grid Solar System

According to a Pew Research Center survey carried out in 2019, there is a growing number of homeowners (46%) who are considering solar systems for domestic use, with 6% having installed solar panels in their homes already.

U.S. Homeowners are Considering Residential Solar Panels

The president and CEO of the Solar Energy Industries Association (SEIA), Abigail Ross Hopper said, “The rapid growth in the solar industry has completely reshaped the energy conversation in this country.”

According to her, “this $17 billion industry is on track to double again in five years, and we believe that the 2020s will be the decade that solar becomes the dominant new form of energy generation.”

What are you waiting for?

Every day when the sun rises, everyone can power their lives! Ipads, TVs, A/Cs, refrigerators, heaters, lights, phones, and lots more, powered by sunlight.  It is a smarter, more reliable, and natural way to power everything in our lives.

Many homeowners deem the off-grid solar system advantageous because of its ability to maximize output and cycle electricity in your home. Many countries are currently facing a power crisis, and a trustworthy, off-grid solar system is the ideal solution.

This complete generator sizing guide for off-grid solar systems covers a wide range of topics, as follows:

  • What is an off-grid solar system?
  • Basic components of the off-grid solar system
  • 5 Reasons why you should use off-grid solar systems
  • Generator backup for solar systems
  • Generator sizing guide for off-grid solar systems – factors to consider

What is An Off-Grid Solar System?

There are mainly three types of solar systems, namely:

  • On-grid solar systems
  • Off-grid solar systems
  • Hybrid solar systems

Types of Solar Systems

Although they all have some components in common like inverters and panels, we will be focusing on the off-grid solar system.

Simply put, an off-grid solar system is a system that is off the grid. It works with solar panels, inverters, charge controllers, and a battery bank to provide renewable energy instead of depending on shared electricity.

The off-grid solar system, also known as the stand-alone power system (SAPS), generates electricity via solar panels, which is used to charge the solar battery with the help of a charger controller.

How Off-Grid Solar Systems Work

Then, an inverter is used to convert the electricity, enabling you to power your home or business appliances.

Saving electricity in a solar battery makes it easy to run your home and business with solar energy round the clock.

Basic Components of the Off-Grid Solar System

The off-grid solar system incorporates four components to ensure maximum functionality. Here they are:

  • Solar panels
  • Solar batteries
  • Solar inverters
  • Solar charge controllers

1.Solar panels

Solar panels are mounted physically on a mounting structure to produce DC power, which is wired through the charge controller before it is stored in the battery bank.

The size and production of a solar panel array depend on the amount of sunlight available in that region, as well as the energy consumption needs and the available usable roof space.

2.Solar batteries

The battery bank of the stand-alone power system stores the energy produced by the solar array during the day to be used anytime, even at night.

Solar batteries allow your home to continue running even after the sun goes down.

Since solar panels are capable of generating excess electricity, the solar storage device charges throughout the day. The solar batteries store energy to help avoid losing so much solar power.

3.Solar inverters

Solar inverters are also called PV inverters. Stand-alone inverters work best for off-grid solar systems.

Stand Alone Solar System Components

You will need a solar inverter to convert the direct current (DC) from the solar panel array into an alternating current (AC). This will allow you to to run your home and business appliances and electronics.

4.Solar charge controllers

Also known as a battery charger, the solar charge controller is vital for the battery to save energy. Its main function is regulating the voltage and current received by the solar battery to prevent either overcharging or damage.

Charge controllers have two main functions:

  • Preventing overcharging of the battery, and
  • Eliminating the reverse current flow that takes place at night from the batteries to the solar modules.

5 Reasons Why You Should Use Off-Grid Solar Systems

As Steve Jobs rightly said, “To me, ideas are worth nothing. They are just a multiplier. Execution is worth millions.”

Are you confused about the best type of solar energy for your home or office?

Many people like you are pondering the same thing. Honestly speaking, both types of solar systems offer their set of advantages and disadvantages. So, it is really up to you to choose the best for your power supply needs.

The tremendous benefits of using off-grid solar energy in your home cannot be overemphasized, especially since it will make you stand out from other homeowners when there is a power outage.

To make things as easy as possible for you, we’re going to give you 5 reasons why the off-grid solar system is more beneficial for your house and office.

1.Low monthly rates

Enlightened Solar helps proud homeowners to save money by installing beautiful solar systems at a fair price.

By using off-grid solar systems, you will be helping the environment and saving money in the long run. You will no longer have to worry about high monthly rates and mounting electricity bills.

The average amount that solar energy homeowners pay monthly is about $84, which varies depending on many factors.

Also, this team of passionate solar professionals will show you the exact costs of every component in the off-grid solar system, providing you with the best value for your money.

2.Keeps the environment clean

How much do you love the environment?

If you love to see your environment green and clean at all times, you should go solar.

Many companies provide electricity using means that are hazardous to the environment. The experienced professionals at Enlightened Solar are eco-friendly and will ensure that you enjoy clean energy from the sun with a minimal carbon footprint.

3.Stable light despite power outages

When there is a power outage caused by a storm and you are grid-tied, you will find yourself in a blackout. Since most home and office appliances run on electricity, you will be helpless until power is restored.

With Enlightened Solar, your energy is stored in case of disasters and you will be fine when others are experiencing power outages.

Sudden natural disasters have caused considerable devastation in different parts of America, making it essential to have a reliable backup. This is achieved by storing energy in batteries so that your home will be powered all the time, irrespective of the weather conditions.

4.A better alternative for rural life

One of the problems faced by people living in rural areas is the high cost of connecting to the main electrical grid, which is usually costly and tedious.

Are you moving to a rural area and worried about powering your house?

With off-grid systems, you can save that extra money, especially if you live far from the main electrical grid. You will also produce and control clean electricity to live wherever you like. This will save you time and money, while still ensuring that you enjoy a stable electricity connection.

Save yourself the chore of jumping over the hurdles associated with being grid-tied by literally going off-grid.

5.Easy installation

The installation process for off-grid solar systems is very straightforward because the equipment needed to run it does not depend on the grid to work. There is no need for a complex infrastructure or connection.

All that is required to install this system is for you to have some background knowledge of basic tools. You will only need a professional to guide you and show you the ropes.

Also, there is no need to undergo the expensive process of the trenching required when putting the collected solar energy on the grid.

Generator Backup for Solar System

Do you want to enjoy full energy independence?

Do not forget that there will be days without sunshine. On such days, you will still need to generate energy. Hence the need for a generator to give you full energy independence.

A generator can serve as a good backup plan for the days you do not have enough natural light to generate solar energy and power your home appliances. Although not all solar power systems require a generator, some living or working conditions require a viable backup solution.

So, where using a wind turbine as a secondary source of power is impractical, you should use a generator.

However, not all generators are suitable for off-grid solar systems. The two main types of generators that can be used for off-grid solar systems are:

  • Conventional generators, and
  • Inverter generators.

Generator Sizing Guide for Off-Grid Solar Systems – Factors to Consider

Off-grid solar systems need a backup plan for times when the solar system does not produce enough energy to meet your required needs. Most of these systems pair with a generator. Just make sure you choose models that are durable, cost-effective, and reliable.

Are you thinking of having an off-grid solar system installed in your home?

Then you should consider buying the off-grid solar system from experts. They will help you choose the one that best suits your home design. Installing the wrong systems can lead to adverse consequences as the electric output may not be a good match for your appliances.

Here are some factors to consider when choosing the size of the generator for your solar system:

The size of the generator

Generally, the output of the generator should be about double the size of the continuous output of the inverter. The reason for this is that the generator will have to charge the batteries while it is powering loads.

For instance:

You should pair a 4,000-watt inverter with an 8,000-watt generator.

If you have loads of 4,000 watts, and a charger of 60 amps at 48 volts, you should expect continuous power of about 7kW.

That is:

60a x 48v = 2,880 watts + 4,000 watts = 6,880 watts

The minimum generator size you should go for is 8kW. This size can power loads and still have the power needed to charge the battery bank as well.

You could round up a little to give more headroom for the generator. Your generator will need this because it is likely to lose some power when it is at higher elevations.

Larger or smaller generator?

What size generator is best for off-grid solar systems?

Larger generators are great for households or offices with large loads like air conditioners. A 4000w inverter is usually suitable for 12kW and 14kW generators in the off-grid system. However, larger generators tend to burn more fuel than smaller ones.

Would you rather go for a smaller generator?

Smaller generators, on the other hand, require that you adjust the settings to limit the output of the battery charger for them to work well. Most battery chargers will need you to adjust the settings for the charge rate and AC input amperage. Also, the generator’s voltage has to match that of the inverter.

Type of generator fuel

What kind of fuel will be more efficient and pocket-friendly for your generator?

Most of the standby home generators run on diesel, propane, or natural gas.

Diesel generators have the advantage of lasting longer and being more fuel-efficient than either natural gas or propane. However, it costs two or three times more than the alternatives.

Most people who use off-grid solar systems use generators that can be configured to work with either propane or natural gas.


You need to take a close look at the warranty of your generator to ensure that it covers prime power or off-grid applications.

There are generators that offer up to 18 months or 1000 hours warranty for off-grid use. This is in addition to the 10-year installation warranties and 25 years of energy production warranties you will get from trusting Enlightened Solar with your renewable energy needs. It’s a great deal!

1800 RPM generators vs. 3600 RPM generators

Typically, generators operate at an engine speed of either 1800 RPM or 3600 RPM.

What’s the difference between the two and which one will be best for you?

The difference between the two engine speeds is based on the alternator that is used, as well as the engine design.

1800 RPM generators are superior to 3600 RPM generators in terms of their fuel efficiency. However, they are pricier than 3600 RPM generators. Although 3600 RPM generators are cheaper, they are not as efficient as 1800 RPM generators.

2-wire start

When pairing your off-grid generators with solar power systems, you need to use 2-wire start capability. This will elicit a better response from the automatic generator start (AGS) functionality.

The AGS kicks in to start the generator and recharges the battery bank when your batteries drop below a particular voltage.

A 2-wire start is not an electric start. While some generators have an electric start/stop button, they cannot be controlled with the 2-wire signal. This means that the inverter will not communicate with the generator before the AGS mechanism is triggered.

Are you ready to be a proud homeowner with full energy independence?

Michelle Davis, the Senior Solar Analyst at Wood Mackenzie, forecasted that “by 2024, there will be on average, 1 solar installation per minute. That’s up from one installation every 10 minutes in 2010.”

From this latest forecast, it is abundantly clear that having an off-grid solar energy system is the best option for your home. As a homeowner, you deserve to generate your own power for long-term use.

Solar design is an art and Enlightened Solar has the expertise, experience, and desire to power your home in a beautiful way.