How many solar panels do I need to be off the grid?

Going off-grid is a great way to meet your energy needs if you live in a remote location, want to be energy independent, save money on monthly utility bills, and live a sustainable lifestyle. Although off-grid solar used to be cost prohibitive due to the high cost of batteries and inverters, the cost of those technologies continue to drop and efficiency continues to rise, making off-grid more feasible for more individuals. How many solar panels do you need to go off-grid and is it worth it? What should you consider when deciding whether or not off-grid solar is right for you?



What is off grid solar?

Off-grid solar systems, or stand-alone power systems, are connected to the electrical grid and produce enough energy through the usage of solar panels and battery storage without having to tap into the electric grid. Historically, off-grid systems have been out of reach most people because of the high costs of inverters and batteries, but as mentioned before those prices keep dropping.



Off-grid vs. on-grid: What are the main differences?

Off-grid solar systems (stand-alone power systems)

Off-grid systems utilize batteries to store energy produced from solar panels. Because you’re not able to tap into the grid, your system should be designed to fit a variety of needs throughout the year, especially in the winter when there are fewer sunlight hours. If you live in a remote area without reliable and affordable access to the grid, off-grid solar can be a great way to meet your energy needs.

On-grid systems (grid-tie solar systems)

On-grid systems are the most common and widely used systems. You can simply use energy from your panels when they are producing, and then at night when your panels are not producing power, your system can tap into the grid. Excess solar that’s produced during the day can be credited to your utility’s account with a mechanism known as net metering. Then you can use that power at night without paying extra. You do not need a battery bank.

One important thing to consider when it comes to on-grid systems is that they do not function during a blackout. This is because it would be a safety concern for a system to push power into the grid when utility workers may be out making repairs to the network.

On-grid systems with battery storage (hybrid systems)

With the decreasing costs of batteries, more and more people are choosing to add battery storage to their on-grid projects to be able to take advantage of the benefits of both on- and off-grid systems, such as having energy access during blackouts and having to pay for less energy from the grid.



Is going off-grid right for me?

Going off-grid is not for everyone, but if these things apply to you, it may be a great solution:

  • You live in a tiny home, cabin, or in an isolated area without reliable access to electricity.
  • You live a mobile lifestyle in a van or RV.
  • You want to be green and energy independent.
  • You want to stop paying money to the utility.



How can I make my solar system off the grid?

If you want to go off-grid, there’s a few steps in a process that we recommend you follow before installing panels on the roof of your home.

1. Evaluate your energy needs: You’ll first need to size your system based on your energy needs. The Renogy solar panel calculator is a great tool that makes it a quick and easy process to help determine your specific needs. The solar sizing calculator allows you to input information about your lifestyle to help you decide on your solar panel requirements. You’ll just need to know what total watts your electronics will consume, how long you plan on running the devices, your charge controller efficiency, and average sun hours per day. The solar panel calculator will then be able to tell you the minimum and recommended system size, as well as the recommended battery output. Having an accurate understanding of your energy needs will give you a better idea of the costs and ensure you don’t under- or over-build a system.

You’ll also want to do some planning around your roof and how you will mount your panels at this stage to determine where your panels should be mounted for maximum sunlight and efficiency. Is your roof near the end of its life? If so, it might be time to consider getting a new roof before installing panels on it. We’d recommend hiring a professional to evaluate your roof if you’re not sure it can withstand a solar installation.

2. Consider what appliances you need and which you don’t: Another thing to consider is taking into account what appliances use the most electricity and whether or not you could go without them. The appliances that use the most electricity in your home include lighting, air conditioners and electric furnaces, refrigerators, water heaters, electric ovens, dishwashers, and clothes dryers. Want to avoid installing a large system? Maybe consider hanging up your clothes to dry or washing dishes by hand. Perhaps a wood stove is a better option to warm your home than a furnace.

3. Look into your solar options. Consider a solar panel kit: Solar panel kits make it easy to ensure that you have all the parts you need and that they will safely and efficiently work together. Renogy has a range of different solar panel kits for those interested in installing solar on their own.

Starter Kits are designed with beginners in mind and are available with easy to handle, small solar panels rated for systems between 50 and 400 watts.

Premium Kits include 100W Eclipse solar panels for systems between 100 and 800 watts.

RV/Van Kits are the perfect addition to any RV, motorhome, or mobile application. 100 to 400 watts systems are available, and they also have folding suitcase and flexible solar panel options.

Cabin and Shed Kits are designed for autonomous use away from the grid. These off-grid kits come with everything to power up a cabin, tiny home, or other small scale building. They come in sizes ranging from 1000 watt to 4500 watts.

4. Installation! Because you’re not connected to the grid, you can often install an off-grid system yourself. Keep in mind that if you’re installing solar on your home and will be connected to the utility, many utilities and jurisdictions require that solar be installed by a certified installer. The fact that you’re not connecting to a grid is a great reason why people wanting to go the DIY route often go off-grid.



How many solar panels do I need to go off-grid?

For the cases of this example, let’s say we have some 300 watt solar panels, and you’re looking to provide power for your home. You don’t have access to the grid and installing off-grid solar on your home is your best option for meeting your energy needs.

Let’s assume that each panel gets around 8 hours of sunlight per day on your rooftop. A 300 watt panel receiving 8 hours of sunlight per day will produce almost 2.5 kilowatt-hours per day. If we multiply this by 365 days per year, we get a solar output of about 900 kilowatt-hours annually. In short, each panel will provide 900 kilowatt-hours each year.

How much energy does your home use? Most data suggests that a typical American home (2,000 square feet home) consumes approximately 11,000 kilowatt-hours annually. So, when we divide our total consumption by the expected output of one solar panel, we see that roughly thirteen solar panels of this size would be enough to power a home of that size. If you have a smaller home or are powering an RV, your energy needs will be much lower, and you’ll need fewer panels.



12v, 24v, or 48v? Which is best?

As you’re shopping you’ll come to learn that panels and inverters typically come in either 12, 24, or 48 volt options. Most RV’s and boats typically use 12V battery banks, so people usually stick with 12V panels. 12 volt systems used to be the standard for homes, but today, many larger home systems are rated at 24v or 48v.

12v systems are good for many DIY solar scenarios, such as RVs/motorhomes/vans, camper trailers, and small cabins or tiny homes. If your energy needs are around 1,000 to 5,000 watts, go for a 24 volt system. If your energy needs are over 3,000 watts, go for a 48 volt system. Large off-grid houses often use 48 volt systems.



How many batteries do I need?

As mentioned before, you’ll need a battery bank in an off-grid solar installation. It’s very important to properly size your deep cycle battery bank. The amount of battery storage you need is based on your energy usage. Energy usage is measured in kilowatt hours. So if you need 500 watts for 8 hours per day, then your energy usage is 4kWh per day. A battery capacity of 4 to 8 kWh is usually sufficient for an average four-person home. Your energy needs may greatly differ from that depending on what you’re powering in your household or how big your home is.



How much does it cost to go off-grid in Australia?

Although the cost can vary from home, the cost of an off-grid system for a typical Australian home ranges between $25,000 – $45,000.



How much does it cost to go off-grid in the U.S.?

The cost of a full off-grid system for a home in the U.S. is comparable at around $30,000-$45,000. If you’re installing on a small home, cabin, or RV, that cost will be much less.



Conclusion

Installing an off-grid solar system on your home, cabin, RV, or van is a great way to meet your energy needs if you live a remote or mobile lifestyle. Before you install any solar panels on your roof, make sure you take the time to accurately calculate your energy needs. Once you know how much energy you’re using, you’ll be equipped to build the perfect solar installation for your home. And if you want additional help, you can purchase one of Renogy’s solar panel kits to make going off-grid even more seamless and headache-free. Before you know it, you’ll be cooking and relaxing in your off-grid home, with the peace of mind knowing that you’ll have reliable, affordable energy access for years to come.