Off-grid solar systems: An introductory guide

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off grid solar system
Pictured: An off-grid home. Image source: energy.gov

Off-grid solar means meeting all your energy needs from the power of the sun — with no help from the electrical grid. To make this possible, you need to install a solar power system paired with an energy storage system, like a solar battery, at the site of power consumption (your home).

Installing an off-grid solar system was once a fringe concept due to its large space requirements and prohibitive costs. But advances in solar tech over the last decade have made solar equipment more efficient and less expensive, helping to push them into the mainstream. It’s now a fairly common sight to see RVs and country cabins powered entirely by off-grid solar systems. 

If you’re thinking of buying an off-grid solar system for yourself, you’ve come to the right place. In this blog, what you need to know about off grid solar systems before buying one. We’ll help you figure out if an off-grid solar system is right for you, and tell you how to buy the right system for your needs.

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    What is an off-grid solar system?

    While many people think only of solar panels when they hear “off-grid solar”, the reality is that you need to add many other components to get a functioning off-grid PV system.   

    A complete off-grid solar system is one that has all the necessary equipment to generate, store, and supply solar energy onsite. As off-grid solar systems operate without a connection to any external power source, they are also referred to as “standalone solar power systems”.

    Unlike other types of solar setups, such as the more common grid-tied solar system, off-grid solar systems rely on batteries to provide power when the sun isn’t available. 

    Batteries, however, are costly — much more so than the solar panels they are paired with. The need for ample battery storage in off-grid solar systems makes them much more expensive than grid-tied solar systems.  

    What are the different uses of off-grid solar power?

    One of the biggest advantages of solar as an energy source is its scalability and modularity, which is the degree to which a system’s components may be separated and recombined for flexibility and variety in use. 

    It works at all levels, from small devices such as solar phone chargers, all the way up to a system that can power a factory.

    Here are some of the most common applications of off-grid solar:

    • Providing a charge to a portable phone or tablet charger
    • Powering the appliances in an RV
    • Generating electricity for small cabins
    • Powering small energy-efficient homes 

    It’s worth noting where off-grid solar systems do NOT make sense: where there is easy access to the utility power. This covers situations where one is looking to power a home in a home in a city, suburb or town. 

    If that’s you, you can save much more by opting for a grid-tied or hybrid solar panel system — or even just sticking solely to grid power — depending on the economics of solar in your area. 

    Check if solar is worth if it where you live

    What equipment does an off-grid solar system require?

    Here’s a list of all the equipment required for a functioning off-grid solar system:

    • Solar panels
    • Solar charge controller
    • Solar inverter(s)
    • Solar battery
    • Mounting and racking system
    • Wiring
    • Junction boxes

    Diagram shows power flowing from solar panel to charge controller, then to either battery or inverter

    Electricity from the solar array flows to the charge controller - from there it is either sent to the battery for storage, or to the DC-AC converter (aka inverter) to supply power to the home. 

    For more information about each of these components, check out this blog on solar panel equipment.

    How to size an off-grid solar system

    Deciding on the size of the system you need is an early and absolutely crucial step when it comes to installing an off-grid solar system. 

    It will affect the kind of equipment you need, how much work the installation will involve, and, of course, the total cost of the project. Solar setup sizes are based on the amount of power the system needs to provide. 

    There are two different ways to figure out the number you need, and they are based on:  

    1. Your current usage
    2. Load evaluation

    Basing solar setup size on usage 

    You can use this option if your aim is to maintain your current lifestyle as you switch from grid-tied to off-grid solar. To do this, you can simply refer to your monthly power bills to determine your electricity usage in kilowatt hours. 

    You can then size an off-grid system of that size, although you’d want to go a bit bigger — say 10% more — to allow for solar inefficiencies. 

    Basing solar setup size on load evaluation 

    The second option is to perform a complete load evaluation to determine how much power you’ll need. 

    1. Calculate total electricity usage needs 

    Begin by listing out all the appliances you plan to use, and how many hours you’ll be using each of them. This allows you to calculate the power consumption of each appliance, as well as your total power consumption over a day. 

    Knowing how many kWh in a day you’ll use will allow you to size your solar panel array, as well the solar battery storage

    2. Calculate instantaneous load requirements 

    You’ll also have to calculate how many appliances you might run simultaneously. This will help you calculate instantaneous wattage requirements, which you need to know in order to size the inverter properly (the inverter runs the AC loads).

    3. Decide on battery storage capacity 

    Next, you’ll need to decide how much energy storage you want. Do you want to cover usage for just one day, or do you want to have extra backup capacity? 

    When it comes to solar battery backup, the rule generally is you'd want enough storage to cover at least 2-3 days of usage during the highest usage time of year.

    4. Design a system around your number from Steps 1-3 

    Figuring out the sizes of these three crucial components — the solar panels, inverter, and battery storage — is usually enough information for solar equipment vendors to customize a complete off-grid kit for you. 

    How much does an off-grid solar system cost?

    The prices of off grid systems range from about $50 (for a phone or tablet charger) to tens of thousands of dollars. That’s because off grid solar has such a huge variety of applications. 

    If we talk specifically about off-grid solar kits that can power an entire home, then prices range from $12,000 to $50,000. 

    You can get an idea of pricing from the table below; it shows popular off-grid kits for different end-use requirements:

    Name Peak output Battery Price* Suitable for
    Hiluckey 5 W 92.5 Wh lithium polymer $47 Phone and tablet charging
    WindyNation 400 W 3.6 kWh lead acid $1,690 RVs, camping
    AltE 1.83 kW 13 kWh lead acid $12,046 Cabin, tiny home
    AltE 4.88 kW 25.9 kW 48V lead acid $15,160 Small home
    Wholesale Solar 11.34 kW 55.2 kWh 48V lead acid $35,576 Mid-size home, farm/ranch
          *Prices as of Nov 13, 2020  

    Please note that the costs mentioned are only for the off grid solar panel kits, i.e. just the equipment. If you use a professional solar company for installation, there will be additional charges for labor; whereas with a DIY there may be some extra costs for permitting and tool requirements. 

    Learn more: 11 step guide to DIY solar

    Get an accurate estimate of yearly solar savings for your specific home

    The impact of battery type on cost

    With the exception of the Hiluckey phone charger, all of the kits above include AGM lead acid batteries. AGM (Absorbent Glass Mat) batteries are a popular choice for off-grid solar systems because they are low maintenance, convenient, and relatively inexpensive as compared to lithium batteries. 

    Best places to buy off-grid solar system kits

    The buying process for off-grid systems will vary based on the size of the system you want. 

    Best place to find turnkey solar installers 

    If you’re looking for a company to handle the complete installation process for an off-grid solar system - from system design and procurement to installation and permitting and inspection - then check out the SolarReviews solar companies database

    It’ll show you the best local solar companies in your area based on consumer reviews. 

    Best place to buy large and medium off-grid solar system kits 

    If you’re a DIY’er looking to power an entire structure - a shed, cabin, house, or even an farm or ranch - then you’ll want to buy from a reliable solar equipment distributor. Unbound Solar (formerly known as Wholesale Solar) and the altE Store both have great kits that come with plans and support.

    Best for small and portable off-grid solar systems 

    For people looking for portable solar power for when they’re camping or using RVs, there are many options, including Home Depot, Amazon, Best Buy etc. Brands that have good reputations are Grape Solar and Renogy; both are American companies. 

    However, there are now many brands in the market, many with much lower prices; just make sure to check reviews and warranty details before making a purchase. 

    The advantages of off-grid solar

    Over 300,000 homes are believed to be using off grid power sources for their energy needs.

    Here are a few reasons why some Americans choose to live off the grid.

    Freedom from the grid 

    This is the primary reason why people in blackout-prone regions are interested in off-grid solar. When connected to the grid, you are dependent on an external supplier — the utility company — for all your power.

    When the grid shuts off, so does your power supply. This dependence doesn’t seem to be a problem until you are hit with blackouts and power failures, as those who suffered through the California blackouts of 2019 can attest. 

    It’s good for the environment 

    Going off-grid reduces carbon emissions. Since most of the electricity supplied through the grid comes from burning fossil fuels, producing your own power through renewable resources (solar, wind, hydro) drastically reduces your carbon footprint.

    Encourages a more energy-conscious lifestyle 

    When you’re connected to the grid, it’s easy to be unaware of your power consumption habits — you consume electricity, pay the bill when it comes, and that’s that. It disconnects you from where the electricity is coming from and where it’s being used.

    Your attitude when it comes to power changes completely when you go off-grid. In order to ensure you don’t run out of electricity, you will have to closely follow your energy generation and also re-evaluate and rationalize your energy consumption. 

    Often the only feasible option 

    When you’re seeking to power a building in a really remote location - say a hunting cabin out in the woods - there’s a good chance there’s no grid to connect to at all. 

    If you contact the utility for a connection, they will probably tell you that you are out of their coverage area. Alternatively, they could offer to lay the wire to connect you to the grid — but only at an astronomical cost. 

    That means that you’ll have to produce your own power. You could use a backup generator, but fuel for it is expensive, while renewable energy like hydropower and wind aren’t available most places. This leaves solar as the only practical option for off-grid power. 

    A charming A-frame cabin with rooftop solar panels, surrounded by pine trees.

    A beautiful off-grid A-frame cabin in the Catskill Mountains. Image source: Chris Daniele via OffGridWorld 

    The disadvantages of off-grid solar

    In spite of some great benefits, there are several valid reasons why the vast majority of US households choose to remain connected to the grid when they install solar on their homes. 

    Some key issues with going off the grid include:

    Off-grid might actually be illegal where you live 

    While installing solar panels and generating your own electricity is gaining traction across the US, there are some counties that have made it illegal to completely unplug from the grid. Such legal restrictions related to going off-grid are generally more common in metropolitan areas than in more rural areas.

    Off-grid solar systems are expensive 

    A solar panel setup that supplies all the energy needs of a home tends to be very expensive. 

    Compared to a grid-connected solar system, an off-grid solar system requires more panels, an inverter with a higher voltage capacity, and a large amount of solar battery storage. 

    And since there’s no grid to fall back on, you will want to purchase a gas or diesel-powered backup generator, and these are very expensive to run. This also adds greater urgency when repairing faults in your off-grid system because generators cannot be relied upon for too long.

    Off-grid solar is time-consuming 

    Making the commitment to produce enough power to meet all of your household’s needs is an extremely challenging task.

    A fairly advanced understanding of how electricity works is required. Because generating power is an exact science, you will have to spend time calculating the precise amount of power that needs to be generated, based on your energy usage patterns. 

    Time will need to be spent ensuring you are keeping power waste at a minimum. And because power generation can be unpredictable, you will have to constantly monitor your power supply.

    You also must learn about the equipment used to generate power and be capable of fixing any and all faults.

    No SGIP rebate for off-grid solar in California 

    California California’s Self Generation Incentive Program (SGIP) is one of the largest battery storage incentives in the country. Eighty percent of the incentive's budget is allocated for battery storage.

    People can save thousands of dollars on batteries with the SGIP rebate, especially if they live in fire hazard districts. But the catch is that SGIP is only available for grid-tied solar systems with battery backup — and not for pure off-grid solar systems. 

    There are better alternatives for backup power  

    The biggest reason why going off-grid may not be for you is because there simply is a better alternative.

    The easiest and most efficient way to protect yourself from blackouts, while saving money on your power bills and helping the environment, is by installing a grid-tied solar system with battery backup. Another name for this type of setup is a hybrid solar system

    These ‘hybrid’ systems, which use battery solutions such as the Tesla Powerwall, are cheaper than off-grid systems and also qualify for incentives such as the SGIP rebate

    Off-grid solar entails major lifestyle sacrifices 

    Talk to anyone with an off-grid solar system, and they will tell you the same thing: relying on off-grid power requires you to completely reevaluate your relationship with energy. 

    The high cost of off-grid solar means homeowners are forced to install relatively small systems. The amount of power available is often further limited by inclement weather: a cloudy day may result in power output reductions of 50% or more. 

    Running out of power leaves you in a bind. You will either have to wait for the sun to come out again, or generate power using a backup diesel generator (if you have one). The first option is very inconvenient, while the second is very costly. 

    These constraints can affect every aspect of your life. Many off-grid folk, for instance, say the need to conserve power means they have to economize on water as water pumps consume a lot of power; this means short showers and less frequent flushing. Air conditioning, an even bigger power guzzler, can only be used for limited periods, if at all. 

    A woman eats in a dark kitchen next to a lit candle.

    Without careful management of your off-grid energy usage, you could find yourself running out of power when you need it. Image source: AP 

    Is an off-grid solar power setup right for you?

    Off-grid solar is the most convenient energy source when it is hard (or impossible) to access the grid. It’s hard to imagine, say, a camping enthusiast forgoing solar in favor of a generator that is heavy, noisy, and requires costly fuel.  

    It is also usually the best option to those committed to a low carbon footprint, sustainability-minded lifestyle. Other renewable energy sources, such as wind and hydropower, aren’t just more expensive, but they also require access to a reliable wind and water supply.

    On the other hand, if you are a typical homeowner living in or near a city or town, then off-grid is almost certainly not for you. 

    This is because off-grid solar systems for homes are expensive and thus rarely yield any savings over utility power. Furthermore, the high cost of off-grid solar means homeowners are forced to install relatively small systems; the limited power they provide imposes major lifestyle sacrifices on the home’s residents. 

    If it’s financial savings you’re interested in, then look at grid-tied solar systems instead. They are the cheapest way to go solar, and in many states they can result in savings of $100,000 or higher. And having a connection to the grid means that you’ll have consistent access to all the power you need. 

    You can learn more about how grid-tied solar systems work here

    If, however, getting a battery backup like the Tesla Powerwall is a priority for you, then consider hybrid solar systems. Hybrid solar systems are grid-tied systems which also have batteries. While hybrid systems are more expensive than simple grid-tied systems — and thus offer lower savings — they are still far cheaper than an off-grid setup.  

    You can check the costs and savings of a grid-tied solar panel system by entering your address into the calculator below. 

    Find out what solar system size you need to offset 100% of your electricity usage

    Key takaways

    • An off-grid solar system uses solar panels, battery storage, and allied equipment to power a location independent of the electricity grid. It has many uses; it can power campsites, RVs, boats, remote cabins, and even family homes.
    • Before buying an off grid system you’ll need to figure out what system size you want. You can figure this out with one of two methods: based on your current electricity consumption or by conducting a thorough load evaluation.
    • An off-grid solar kit that can run a home will cost anywhere from $12,000 to $50,000; and that doesn’t factor in installation, permitting, and fees.
    • Pros of off-grid solar: freedom from utilities, positive environmental impact, a more energy-conscious lifestyle, and the ability to produce power pretty much anywhere in the world.
    • Cons of off-grid solar: it’s illegal in some jurisdictions, very high upfront costs, time-consuming to install and monitor, doesn’t qualify for the SGIP rebate in CA, and it requires major lifestyle sacrifices.
    • If you’re looking for a more affordable way to go solar, consider a grid-tied solar system instead.
     - Author of Solar Reviews

    Zeeshan Hyder

    SolarReviews Blog Author

    Zeeshan is passionate about promoting renewable energy and tackling climate change. He developed these interests while studying at beautiful Middlebury College, Vermont, which has a strong focus on sustainability. He has previously worked in the humanitarian sector — for Doctors Without Borders — and in communications and journalism.

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