How many solar panels to be self-sufficient? 5 Steps

To be completely self-sufficient, how many solar panels do I need?

A typical home requires between 25 and 30 solar panels to cover 100% of its electricity needs. To actually calculate how many you’ll need, there are a variety of variables like the area you live in, panel efficiency, rated power, and your personal energy consumption habit that can affect that number.

A step-by-step approach to building your off-grid solar system

There are five steps to constructing an off-grid solar system, and each step builds upon the previous one. A fully functional solar system should be complete at the end of the process.

Those five steps are:

1. Determine your energy requirements
2. Choose the type of system you wish to build.
3. Calculate the size and quantity of solar panels that will be required.
4. Calculate the amount of battery storage required
5. Choose the system’s auxiliary equipment and install it

Determine your energy requirements

Before beginning any other course of action, you must first determine how much power you will need to generate. This begins with determining where you intend to install your off-grid solar energy system and how you intend to use it.

Is it for your primary residence? Is it for a weekend getaway? What number of people will be using power at the same time? Energy is required for what appliances?

Remember, writing down answers to these questions is only a minute’s work. In this way, you can include them in the specification process.

The number of solar panels required to power your home is based on three factors: annual energy consumption, solar panel wattage, and production ratios. What does this actually mean? The following are the assumptions we made and the math we used:

Annual electricity usage:

The amount of electricity used in your home over a year.

This figure, expressed in kilowatt-hours (kWh), is influenced by the appliances in your home that consume electricity and the frequency with which they are used. Electricity is used by refrigerators, air conditioning units, small kitchen appliances, lights, and chargers, among other things.

The EIA estimates that the average American household uses 10,649 kWh of electricity per year, so we’ll use that number as the size of the ideal solar panel system. This will allow you to offset 100% of your household’s electricity usage with solar panels.

The simplest way to determine your electricity consumption is to examine your utility bills for twelve months and add the figures together to get the annual total.

The wattage of solar panels:

Panel wattage is also known as the solar panel’s power rating. Solar panels produce between 100 and 400 watts of power, and they use watts (W) as their measure of output. To calculate the energy consumption in these calculations, we’ll use a 250-watt panel as an average.

Production ratios:

The production ratio of a solar panel system is the ratio of the system’s estimated energy output over time (in kWh) to the system’s actual size (in W). These ratios are rarely 1:1 – they vary significantly depending on the amount of sunlight your system receives (which is primarily determined by your geographic location).

For instance, an 8 kW system that generates 12kWh of electricity per year has a 1.5 (12/8 = 1.5) production ratio – a perfectly reasonable production ratio in the real world. Because production ratios in the United States are typically between 1.3 and 1.6, we’ll use those two figures as our high and low estimates.

Calculate the Size and Number of Solar Panels Needed

Now that we’ve established our three primary assumptions (energy consumption, solar panel wattage, and production ratios), how do those figures translate into an estimated number of solar panels for your home? The formula is as follows:

Number of solar panels = system size / production ratio / solar panel wattage

First, we take our average system size of 10.649kw and divide it by the production ratio:

10.649 kW / 1.5 = 7 kW

Then we take that number in watts and divide it by the solar panel wattage:

7000 Watt / 250 = 28 solar panels

Thus we need 28 x 250-watt solar panels to be self-sufficient and generate an average of 10.649 kW per year.

Select the System Type You Want to Build

DC, AC, AC hybrid and AC with generator backup are the main solar power systems. To differing degrees, each provides green energy for different scenarios and has its own benefits and drawbacks.

DC solar system

Type of Solar Panel System	Best Suited For
DC	For vacation homes, outbuildings, and other low-power applications.
AC	Can power more appliances and meet higher energy demands. They are frequently used in off-grid homes and businesses.
AC hybrid	It uses solar panels and a wind turbine to generate electricity. These systems are beneficial in many situations where energy is constantly needed.
AC with generator backup	When the sun isn’t shining, a diesel generator powers the batteries.

The most commonly used off-grid solar panel system is AC systems which can power all the most commonly used household appliances.

Calculate Battery Storage Requirements

Once you’ve determined how you’re going to use your off-grid solar power system and the type of system you’re going to install, you’ll need to build sufficient storage to ensure that the energy you generate isn’t wasted. That is where a battery bank comes in handy.

You need to consider the use of your off-grid solar power system. Will it be used daily? Will you need energy only on weekends or holidays? Do you need a steady supply of power to run appliances?

While smaller systems can operate on 12V battery banks, holiday homes and permanent residences may require 24V or 48V battery banks to provide sufficient energy to operate the property.

Then there is the issue of capacity. Your battery bank’s generating capacity should be approximately 10-15% greater than that of your solar panels. This is to ensure that the least amount of energy possible is wasted.

Select the Ancillary Equipment for the System

A fully functional off-grid solar energy system is composed of several components. A typical system consists of solar panels, battery bank, inverter, and all the cabling well as connections.

Given that we’ve already discussed solar panels and batteries let’s briefly discuss power inverters and charge controllers.

A power inverter converts alternating current to direct current or vice versa. Because household appliances operate on alternating current, a system that generates direct current must convert it to alternating current before you can use it. That is the power inverter’s function.

A charge controller is in charge of the system’s energy management. It prevents batteries from being overcharged or over drained. Additionally, it prevents the system from reversing current, which can cause damage.

Additionally, roof or ground mounts, cables, connections, and a router for remote management are required. You must include all of these components in your off-grid solar power system for it to function properly. Fortunately, the vast majority of solar energy kits come with all of these components already included.

Installation of your Off-grid Solar Power System

At long last, the hard work begins. When it comes to installing an off-grid solar power system, the process is quite simple. A large number of kits will include full instructions, and even a novice DIYer should successfully install it.

The simplest and most cost-effective option is ground-mounted solar panels. However, they take up yard space. Roof mounts are harder to manage, but otherwise, you can put this unused space on the roof to use. While there is no “best” option, there are options that you can apply to different situations.