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How to Set Up Off-the-Grid Solar Power

I love off-grid solar. It’s fun to set up, and amazing to have working. I’m happy to share some of my own off-grid experiences to point you in the right direction and help out any other readers who want to learn more. To be clear, going off grid isn’t worthwhile for most people who are grid-adjacent. For remote cabins like yours, though, doing so can be much easier than getting electrical service installed up in the mountains.

Going off grid isn’t worthwhile for most people who are grid-adjacent.

Going into my first solar installation, my situation looked a lot like yours. I needed power at an off-grid location but only on weekends. My power needs were minimal, but I needed the system to be reliable. And since I didn’t know how my needs would change and grow, I had to both stick to my budget and not regret buying cheap. My system was an odd duck, consisting of the cheapest per-watt panel I could find (a 330 W Topoint), a Midnite Solar Kid Charge Controller, a pair of 6 V / 400 Ah flooded lead-acid batteries tied together to make a 12 V system, and a refurbished 2,000 W Magnum inverter. Those main components totaled a bit over 3,000 a few years ago, two-thirds of which was just the inverter. Looking at your situation, however, the total price climbs closer to 5,000 for a more robust system with more flexible upgrade options. That arrangement includes some additional costs for battery cables, breaker boxes, and safety components. With that system as our baseline, we can walk through what will be similar about your system and what will be different.

You said you’d be using around 300 watts for 24 hours, so you’ll need 7,200 Wh of available power each weekend (300 W × 24 h). That’s quite a bit for the small cabin I’m envisioning, so first you should look around and figure out if you can trim your power usage a bit. Whether you’re on grid or off, it’s far cheaper to switch lights to LED bulbs, modernize electronics, and increase your overall energy efficiency than to build a large solar array. Also, heating, cooling, and appliances can be some of your biggest energy loads, so if you want to keep your solar system smaller, consider alternatives for those—propane for cooking or even refrigeration, wood stoves for heat, and if possible, no air conditioning. For now, though, let’s work with the figure of 7.2 kWh being used each weekend. Since you’re in Utah, let’s assume that your cabin and solar panels will get around five hours of direct sunlight per day.

The total price climbs closer to 5,000 for a more robust system.

A 330 W panel like the one I used should generate around 1,500 watt-hours per day (330 W × 5 h, rounded down to be safe). Like me, you could store that power all week in a large battery bank and have around 7,500 Wh (1,500 Wh × 5 days), or 7.5 kWh, in your battery bank for the weekend. But this method isn’t common for off-grid sizing, and you’ll see later that expensive batteries and other components mean you’re better off with more panels instead. To estimate the number of panels you need in a more traditional setup, then, you’ll need to have enough generation capacity for a single, average day’s consumption. With a need to bank about 7.5 kWh of power each day, and with five hours of usable sunlight per day, you’ll require 1.5 kWh of solar panels (7.5 kWh ÷ 5 h). If you use the Suniva panels that we like, you’ll end up with six 280 W panels, which will give you around 1.6 kW (280 W × 6) at the ready. You could probably find some cheaper panels, but we’ll call that 1,900 for your budget.

A great solar panel

Made by a reputable firm with a strong warranty, this module provides good output without a premium cost.

Buying Options

Unlike a grid-tied system, which sends solar power straight from the panels to the inverter and then to a home’s power-distribution panel, your panels will feed into a charge controller. The charge controller translates the amperage and voltage from your panels—which fluctuate all over the place depending on the sun’s intensity and angle—to the very specific amperage and voltage that your batteries need at different points of their charge cycle. My option, the Midnite Solar Kid, isn’t quite up to your task. The charge controller I use for my current system is a Morningstar TriStar TS-MPPT-30, and that model should serve you well; it’s currently available for 330.

From your charge controller, the power will travel to your battery bank. While solar panels are sized to match daily power use, battery banks are sized to match the number of days you can go without sun. This is where your weekend use gets tricky. If you want to be able to use power when the weather has gone to pot, you’ll need your whole usage—7.2 kWh—saved up. Anyone else can look at a power bill, divide the kWh by 30, and get an idea of how much power you’d need each day. Larger systems use higher-voltage batteries, but you can get away with a simple 12 V system. To keep your batteries in tip-top shape for years, you should plan to use about half their capacity. So this 7.2 kWh requirement just became a 14.4 kWh battery requirement. In a 12 V system, that’s 1,200 Ah (14,400 Wh ÷ 12 V). Yikes. You’ll need six of these Rolls Surrette batteries similar to mine, costing up to 2,200.

Look at a power bill, divide the kWh by 30, and get an idea of how much power you’d need each day.

If you’re budget-conscious, don’t even think about going to lithium-ion batteries just yet. The Tesla Powerwall, which keeps making headlines, costs 3,000 wholesale for 6.4 kWh of capacity—the price won’t come down substantially for a few more years. Luckily, batteries are an easy component to upgrade as your budget allows—you can tack on extra lead-acid batteries in a year or two, and no other equipment will need an update. But be ready: These buggers are like three car batteries stacked together, and weigh over a hundred pounds. Each. Let’s start you with four, plan to be miserly, and call it 1,500.

If you’re budget-conscious, don’t even think about going to lithium-ion batteries just yet.

Your inverter will turn all that stored-up DC power into AC power so that you can use standard household electronics. The maximum output of the inverter will be the maximum you can run all at once. You say you use 300 W per hour, but if that’s sometimes a 1,500 W microwave and sometimes a 2,000 W blender, you need an inverter to match that maximum. Such a component gets expensive, so let’s assume you’re mostly running some lights, a laptop, and maybe a TV, and you’re planning to shift any truly heavy loads such as power tools to a backup generator. I use a 2,000 W Magnum inverter, and I love the quality and accessory components, but even the company’s 1,000 W (and 1,000) model might be overkill for you. If you have room in the budget, I’d definitely recommend it. To keep things simple, though, you could go with a less expensive model like this 1000 W (400) example from Cotek, though I don’t have any experience with that company’s devices. I’d recommend sticking to a pure-sine-wave inverter to avoid any problems down the line, but you could also save money by choosing a much less expensive modified-sine-wave inverter. Sometimes those work great; my old one’s worst problem was an obnoxious but quiet buzz that persisted no matter what I did. A cheap in-car inverter I once used started to smoke when I tried to charge a laptop. A solid, small inverter might cost you around 500, but this is an area where you’ll get what you pay for in quality and warranty support.

That puts us at 1,900 for panels, 330 for a charge controller, 1,500 for batteries, and 500 for an inverter. That’s 4,230 for the key components, which isn’t cheap. I probably sank another 600 into sensors, wires, cables, breakers, and a few tool upgrades, so your budget for this build should be about 5,000. If your cabin is subject to building permits, you’ll need to factor those in, and potentially the cost of an electrician. Cutting your power consumption will let you install a smaller and cheaper system, though. And with planning, creativity, and input from your vendor, you can find ways to start small and scale up without wasting money on equipment you’ll outgrow in a year. Someone outfitting a full-time home will want to invest in higher-end gear, but you’ll need to decide what the goal is today versus five years from now. Heck, if you don’t want this headache and don’t need traditional AC outlets wired up throughout your cabin, you could be judicious about your power usage and piece together a plug-and-play system from a company such as Goal Zero.

With planning, creativity, and input from your vendor, you can find ways to start small and scale up without wasting money on equipment you’ll outgrow.

When it comes time to install solar, I’ve found that the biggest challenge isn’t from hooking up your brand-new components—if you’re handy enough to keep an off-grid cabin going, I bet you’re handy enough to wire solar. The biggest problems come from leftover problems in aging wiring; when renovating and upgrading our RV, for example, I spent an entire week with multimeters and tone probes to map out (and fix) some mysterious, undocumented wire runs. But the end result is relatively straightforward: Your panels will be wired together and fed into your charge controller, your charge controller will send power to your battery bank, your battery bank will send power to your inverter (via amazingly thick cables, so keep them near each other), and your inverter will output AC power into a breaker box. Almost every step should be protected by fuses or breakers rated for DC power, and the wiring needs to be rated for the amperage and voltage loss that you plan for. Once power leaves the inverter, you have standard AC wiring—and the usual rules for basic household electricity—the rest of the way.

Compared: Grid-tied, off-grid, and hybrid solar systems

There are three types of solar panel systems: grid-tied (on-grid), off-grid, and hybrid solar systems.

Each type of system has a unique setup that affects what equipment is used, the complexity of installation, and, most crucially, your potential costs and savings.

What would be the best in your situation? Let’s take a closer look at the benefits and downsides of grid-tied, off-grid and hybrid solar systems.

Calculate the price of solar panel installation on your home

Grid-tied solar systems

Grid-tied, on-grid, utility-interactive, grid intertie, and grid backfeeding are all terms used to describe the same concept – a solar system that is connected to the utility power grid.

DC electricity generated by the solar panels is sent to the inverter, which converts the power into AC electricity. This electricity is first used to service the home loads, while all surplus energy is exported to the grid in return for electric bill credits.

Benefits of grid-tied systems

A grid connection will allow you to save more money with solar panels through net metering, lower equipment and installation costs, and better efficiency rates.

Save more money with net metering

Your solar panels will often generate more electricity than what you are capable of consuming. With net metering, homeowners can put this excess electricity onto the utility grid instead of storing it themselves with batteries.

Many utility companies are committed to buying electricity from homeowners at the same rate as they sell it themselves. As a homeowner, you can use these payments from your utility to cancel out your electricity usage charges. by up to 100%.

Net metering plays an important role in how solar power is incentivized. Without it, residential solar systems would be much less feasible from a financial point of view.

Lower upfront costs and ease of installation

Grid-tied solar systems are the only type of solar system that don’t require a battery to function. This makes grid-tied systems cheaper and simpler to install, and also means there is less maintenance required.

You can use the utility grid as a virtual battery

The electric power grid is in many ways also a battery, without the need for maintenance or replacements, and with much better efficiency rates.

According to EIA data, national, annual electricity transmission and distribution losses average about 7% of the electricity that is transmitted in the United States. Lead-acid batteries, which are commonly used with solar panels, are only 80-90% efficient at storing energy, and their performance degrades with time. In other words, more electricity (and more money) goes to waste with conventional battery systems.

Additional perks of being grid-tied include access to backup power from the utility grid, in case your solar system stops generating electricity for one reason or another. At the same time, you help to mitigate the utility company`s peak load. As a result, the efficiency of our electrical system as a whole goes up.

Equipment for grid-tied solar systems

There are a few key differences between the equipment needed for grid-tied, off-grid and hybrid solar systems. Standard grid-tied solar systems rely on the following components:

Grid-tie inverter (GTI)

What is the job of a solar inverter? They regulate the voltage and current received from your solar panels. Direct current (DC) from your solar panels is converted into alternating current (AC), which is the type of current that is utilized by the majority of electrical appliances.

In addition to this, grid-tie inverters, also known as grid-interactive or synchronous inverters, synchronize the phase and frequency of the current to fit the utility grid (nominally 60Hz). The output voltage is also adjusted slightly higher than the grid voltage in order for excess electricity to flow outwards to the grid.

Microinverters

Microinverters go on the back of each solar panel, as opposed to one central inverter that typically takes on the entire solar array.

Microinverters are certainly more expensive, but in many cases yield higher efficiency rates. Microinverters are particularly useful if you have shading issues on your roof.

Power meter

Most homeowners will need to replace their current power meter with one that is compatible with net metering. This device, often called a net meter or a two-way meter, is capable of measuring power going in both directions, from the grid to your house and vice versa.

You should consult with your local utility company and see what net metering options you have. In some places, the utility company issues a power meter for free and pays full price for the electricity you generate; however, this is not always the case.

See how much a grid-tied solar system can save you annually

Off-grid solar systems

An off-grid solar system (off-the-grid, standalone) is the obvious alternative to one that is grid-tied.

For homeowners that have access to the grid, off-grid solar systems are usually out of question. Here’s why. To ensure access to electricity at all times, off-grid solar systems require high-capacity battery storage and a backup generator. On top of this, a battery bank typically needs to be replaced after 10 years. Batteries are complicated, expensive, and decrease overall system efficiency.

Off-grid systems require large amounts of energy storage as there is no option to import power from the electric grid. As such, they are typically designed using lead-acid batteries, which are a much cheaper alternative to newer (and more efficient) lithium-based solar batteries.

Can be installed where there is no access to the utility grid

Off-grid solar systems can be cheaper than extending power lines in certain remote areas.

Consider off-grid if you’re mor e than 100 yards from the grid. The costs of overhead transmission lines range from 174,000 per mile (for rural construction) to 11,000,000 per mile (for urban construction).

Become energy self-sufficient

Living off the grid and being self-sufficient feels good. For some people, this feeling is worth more than saving money.

Energy self-sufficiency is also a form of security. Power failures on the utility grid do not affect off-grid solar systems.

On the flip side, batteries can only store a certain amount of energy, and during cloudy times, being connected to the grid is actually where the security is. You should install a backup generator to be prepared for these kinds of situations.

Equipment for off-grid solar systems

Typical off-grid solar systems require the following extra components:

• Solar charge controller
• Battery bank
• DC disconnect (additional)
• Off-grid inverter
• Backup generator (optional)

Solar charge controller

Solar charge controllers are also known as charge regulators, or just battery regulators. The last term is probably the best to describe what this device actually does: solar battery chargers limit the rate of current being delivered to the battery bank, and protect the batteries from overcharging.

Good charge controllers are crucial for keeping the batteries healthy, which ensures the lifetime of a battery bank is maximized. If you have a battery-based inverter, chances are that the charge controller is integrated.

Battery bank

Without a battery bank (or a generator), it’ll be lights out by sunset. A battery bank is essentially a group of batteries wired together.

DC disconnect switch

AC and DC safety disconnects are required for all solar systems.

For off-grid solar systems, one additional DC disconnect is installed between the battery bank and the off-grid inverter. It is used to switch off the current flowing between these components. This is important for maintenance, troubleshooting and protection against electrical fires.

Off-grid inverter

There’s no need for an inverter if you`re only setting up solar panels for your boat, your RV, or something else that runs on DC current. You will need an inverter to convert DC to AC for all other electrical appliances.

Off-grid inverters do not have to match phase with the utility sine wave as opposed to grid-tie inverters. Electrical current flows from the solar panels through the solar charge controller and the bank battery bank, before it is finally converted into AC by the off-grid inverter.

Backup generator

It takes a lot of money and big batteries to prepare for several consecutive days without the sun shining (or access to the grid). This is where backup generators come in.

In most cases, installing a backup generator that runs on diesel is a better choice than investing in an oversized battery bank that seldom gets to operate at its full potential. Generators can run on propane, petroleum, gasoline, and many other fuel types.

Backup generators typically output AC, which can be sent through the inverter for direct use, or it can be converted into DC for battery storage.

Hybrid solar systems

Hybrid solar systems combine the best of grid-tied and off-grid solar systems. These systems can either be described as off-grid solar with utility backup power, or grid-tied solar with extra battery storage.

If you own a grid-tied solar system and drive a vehicle that runs on electricity, you already kind of have a hybrid setup. The electrical vehicle is really just a battery with wheels.

In a hybrid solar system, energy generated from the solar panels is first used to service the home’s electrical loads (flow #1). After the home’s energy needs have been supplied, solar power is used to charge the solar battery (flow #2). If there is still a surplus of solar energy, it will be exported to the electric grid in return for credits (flow #3). The system pictured above shows an AC-coupled lithium battery, but hybrid systems can also be designed using either lithium or lead-acid-based DC batteries.

Less expensive than off-grid solar systems

Hybrid solar systems are less expensive than off-grid solar systems. You don’t really need a backup generator, and the capacity of your battery bank can be downsized.

If your battery runs out of charge at night, you can simply buy off-peak electricity from the utility company. This will be much cheaper than operating a generator.

Smart solar holds a lot of promise

The introduction of hybrid solar systems has opened up many interesting innovations. New inverters let homeowners take advantage of changes in the utility electricity rates throughout the day.

Solar panels happen to output the most electrical power at noon – not long before the price of electricity peaks. Your home and electrical vehicle can be programmed to consume power during off-peak hours (or from your solar panels).

Consequently, you can temporarily store whatever excess electricity your solar panels generate in your batteries, and put it on the utility grid when you are paid the most for every kWh.

Smart solar holds a lot of promise. The concept will become increasingly important as we transition toward the Smart grid in the coming years.

Equipment for hybrid solar systems

Typical hybrid solar systems are based on the following additional components:

• Charge controller
• Battery bank
• DC disconnect (additional)
• Battery-based grid-tie inverter
• Power meter

Battery-based grid-tie inverter

Hybrid solar systems utilize battery-based grid-tie inverters, which are also known simply as hybrid inverters. These devices can draw electrical power to and from battery banks, as well as synchronize with the utility grid.

Final thoughts on grid-tied solar systems

The bottom line is this: Right now, for the vast majority of homeowners, tapping the utility grid for electricity and energy storage is significantly cheaper and more practical than using battery banks and/or backup generators.

Off Grid Solar: A Beginner’s Complete Guide

Getting started generating free solar power is really not as hard as it seems. Here, I’ve distilled down everything I’ve learned about off grid solar energy over the last 5 years, in to this easy to follow but comprehensive guide.

Determine your power needs

Pick the right site

Choose your components

Build the battery house

Install the panels

Wire up the system

Enjoy your free power!

Going off grid with solar power doesn’t have to be hard. While there is a lot of terminology to wade through, in this guide I’ll cut through the jargon and simplify the process of building an solar system. And, I’ll save you money at the same time.

Step 3 — Ordering the Right Solar System Components

• The number and size of your solar cells
• The type and size of your charge controller (MPPT vs PWM, etc)
• Your battery bank capacity, while considering battery type
• Choosing the overall voltage of each leg, as well as which loads should be AC vs DC
• The rating of your inverter, if any

Step 4 — Building Your Solar Battery House or Compartment

Once you have the components ordered, you would be ready to build your battery house, which may be a room in your existing home, part of the garage, or a separate shed. Batteries take up a fair amount of room, they need to be protected from kids or critters that might hurt themselves by touching the contacts or might accidentally damage the battery and release the acids inside.

Additionally, most types of batteries need some amount of temperature control, and don’t do well with freezing weather. However, if you go with less expensive unsealed batteries, you will have to build in some ventilation in to your battery house in order to prevent buildup of explosive hydrogen gas, which these types of batteries release in small amounts when charging.

In order to reduce costs, most solar setups have their main power electronics — the charge controller(s) and inverter(s) — as well as safety shutoffs, fuses, and breakers in the battery room as well.

We talk about this in part 3 of this series.

Step 5 — Installing Solar Panels

Finally, it’s time to build the panel support and install the solar array. Solar panels are far more efficient when they directly face the Sun, and they last longer when they are rigid and well cooled. A proper solar support structure can be built in many ways, depending on the materials you have on hand, and the skills you posses. I recommend, at the least, building a south facing A-frame type structure out of wood, or metal, with the ability to manually adjust the tilt of your panels during the summer and winter, which can increase your power output by up to 40% with almost no addition cost.

You could also go all out, and build your own one-axis or two-axis tracking system. Check out the panel installation guide below for more ideas on how to make this work.

Step 6 — Wiring Up for Off Grid Solar

With the panels up, now comes time for wiring of the system. This step doesn’t need to be complex. Going off grid, with a boondocking RV, country cabin, or permaculture homestead, means that your electrical system can be much simpler than gird tie systems.

Going off grid means you have the option to install an all DC system, which can be quite simple and efficient. But even whole home replacement AC systems are possible for the DIYer.

However, if you intend to use your solar system and connect it to a home that is already connected to grid power, you are likely to be legally required to hire a licensed electrician to wire in your system, and you will need additional hardware from your utilities company to make your own energy system work with line power.

We talk about wiring your system in part 3 of this series.

How Many kW of Solar Panels Do I Need?

In order to accurately determine how big of a solar system you need, the first thing you need to do is determine how much energy you are using. Energy is measured in kilowatt hours (kWh), and by the end of this section you should be able to determine exactly how many kWh you use in a day.

How to Measure Your Power Usage

The best and most accurate way to determine your power usage is to measure it yourself. I recommend that you purchased this inexpensive “kill-a-watt” power measuring device for your plug in appliances.

Using the kill-a-watt is simple just plug it into the wall, and your appliance into it. It can provide you with a wide variety of measurements, but the one we really need is watts, or kilowatts.

The simplest way to measure energy is to just set the kill-a-watt to measure kilowatt hours. This measurement takes time to get an accurate reading. Ideally, you would leave it attached for 24 hours, and then you would know how much energy it uses during a full day.

You could also just measure the energy usage for one hour. Then just multiply that number by the number of hours you will use that item during the day.

A third, less accurate but faster option, you is to just measure the watts that the device is using, which shows up instantaneously. No need to wait. But then you have to multiply the watts by the number of hours you would use it per day. But, this doesn’t take into account any fluctuations in power usage that happen naturally happen in most appliances except entirely passive devices such as lights and heaters.

Calculating Your Daily Usage

Now, add up all of the energy measurements that you took all of the devices that you plan to use in a given day. This is your daily energy usage.

It’s important to realize I your energy usage fluctuate throughout the year. You may use lights much longer in the winter when it’s darker, yet the refrigerators will run less. I recommend you take a power measurement both in the winter and the summer, or at least attempt to adjust number of hours used by each device to account for the differences.

Knowing how your power usage varies session ally is extremely important for off grid solar, because solar power production also changes throughout the year. So, it is easy to over or under size your system if you only use a yearly average to plan for your system.

Determining How Much Energy Solar Panels Produce

As you might have guessed, the amount of power that your solar panel produces depends on how much sun they gets. That means during the shorter days of winter you will get less power. Also, cloudy days will give you much less power than sunny days.

Again, the best way to know how much power your solar panels will produce is to measure it. Buy one solar panel and measure how much energy you can produce throughout the year. Not every year is the same, so you will need to oversize your system just a little bit in order to account for usually dark or cloudy years.

However, you may just want to get a rough estimate of how much solar power your panels were produce. Luckily the US government has produced solar power availability data for the entire United States.

The map above shows on average how much power your solar panels will produce per day. The number depends on the color of your area it ranges from about two to eight. This number can be multiplied by the power rating of your solar panels to determine how much power they would produce. So if you live in an area labeled as three on the map and you bought a 1 kW Solar panel array then you would get 3 kWh of energy produced per day on average.

This assumes that you have full access to the sun so long as it is up. If location of your solar panels is partially shaded, especially during mid day, then you will get less power than the map shows.

Also, most of the average power is produced during the summer in most regions because of the longer days and more direct sun exposure. To get a more accurate analysis, go to the NREL website and download detailed maps that show your area in both summer and winter months. This way you can calculate how much power you can produce in the darkest and lightest times of the year.

Choosing the Right Size Off Grid Solar System

You will need to size your solar system so that it can produce enough power to cover your winter and summer needs, which often means most of the year you will be producing more power than you can use.

Additionally, we need to account for the fact that solar systems are not 100% efficient. The process of transferring power from the panels to the charge controller, the charge controller converting it and storing in the batteries, and then the power coming out of the batteries and being potentially transformed into AC, all have some power loss associated with them.

While it is possible to go through each of your components and determine how efficient they are and thus calculate the perfect number of solar panels for your particular system, I generally just go with a 70% efficiency figure for typical after power systems.

To calculate how many kW of solar panels you need, including any inefficiencies in the system, just divide your energy needs by 0.7, or whatever figure you come up with for total system efficiency.

Considering Battery Capacity

Batteries are necessary to run your solar system at night, when no energy is being produced. They also help level out power consumption between sunny days, when you are getting plenty of power, and cloudy days when you won’t be getting so much.

At minimum, your batteries should be large enough to store a full day of charging in the winter. So, if your system is capable of producing 1 kWh during a full day in the winter, then I would choose a battery bank that is capable of storing at least that much.

Battery capacity is measured in amp-hours (Ah) so in order to get kilowatt hours you would need to multiply that number by the voltage of the battery. For many batteries it would be 12 V, although 24V and 48V batteries are available for renewable energy systems.

We will be going into more depth on choosing the proper battery in the next section, but be aware that many types of batteries, particularly lead acid batteries, have a very limited discharge depth. Even ”deep cycle” lead acid batteries should only be discharged to 50% capacity. This means you’ll need to double the size or a number of batteries in your system over what the nominal amp-hour rating would suggest.

Where to Put Your Solar Panels

While the go to place to put solar panels on the roof, roofs are very frequently not the best place to put your solar panels. There are three reasons why I don’t recommend putting solar panels on the roof: roof direction, shading, and access.

Make Sure Your Solar Panels Are Accessible

Lastly, solar panels need to be clean and cool to work a maximum efficiency, and have a nice long life. Dust, dirt, and snow will naturally accumulate on solar panels, which need to be cleaned off periodically. Snow accumulation on your solar panels will reduce their life. Placing your panels closer to the ground where they are easier to access can go along way towards making routine solar panel maintenance actually get done in a timely manner.

Make Sure You Solar Panels Are As Cool As Possible

While solar panels are black, they do not like being excessively hot. Over heated panels produce less power, and they wear out much work quickly. A proper solar panel set up should have at least 6 inches behind the panels where air can flow freely and cool down the panels. Roofs are not great because they tend to be excessively hot already, and while you can buy solar panel mounting racks that do allow for ventilation on the roof, putting them down where it’s cooler may save you a lot of extra money in the long run.

In terms of overall cost of the system, it is best to put the solar panels as close as you can to your home, while keeping them in full sun.

Related Questions

How many solar panels does it take to run a house off grid?

An average size off grid solar system in the US is 5 kW, which means you would need 20 solar panels at 250 W each, or 50 smaller 100 W panels. Whether this would run your house depends on how much sun you get and how much power you use.

What is needed for an off grid solar system

• Solar panels (mono or poly)
• Charge controller (MPPT or PWM)
• Battery bank (lithium, lead acid, or other)
• Inverter (pure sine wave)
• Fuses disconnects
• Copper wire
• Misc connectors

Daniel Mark Schwartz

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Off-Grid Solar System Design Installation Guide

So, you’ve decided to start your journey to off-grid living.- congratulations! Installing an off-grid solar setup can be intimidating, so we’ve put together this complete guide to off-grid solar system design and installation to help guide your project.

Inside, you’ll find a complete overview of the process of going off the grid with solar, including detailed calculations to help you size an off-grid system that precisely fits your needs. We’ll also outline how to build an off-grid solar system that is safe and code-compliant.

Off-grid solar systems are not the same as grid-tie solar systems. With an off-grid system, you are entirely independent of the grid and 100% responsible for your power needs. You won’t be able to harness extra electricity from the utility company. Learn more about off-grid vs. grid-tie systems.

Shop Off-Grid Kits

Ready to add an off-grid solar system to your home? Speak to one of our off-grid solar experts today!

Off-Grid Solar System Components

Here’s a quick overview of the parts you can expect to find in your off-grid solar system. It’s important to pick components specifically rated for off-grid use. For example, most grid-tie inverters are not configured to connect to a battery bank.

Solar Panels

Solar panels absorb the sun’s rays, converting sunlight into DC (direct current) power.

While you may find that some panels are marketed as “off-grid solar panels,” this is a bit of a misnomer. There used to be panels that were designed to match the lower voltages of specific types of charge controllers and battery banks, but the technology has improved enough that the design standard has become outdated. Nowadays when a panel is marketed as off-grid it often means that the wattage is lower than the current standard, and many of the panels marketed this way tend to be of inferior quality.

Now, MPPT charge controllers allow us to make use of standard, mass-produced solar panels in off-grid applications. Any traditional 60/120 or 72/144 cell solar panel will work just fine, and if you have space on your property to mount full-sized panels, that will be your most cost-effective option.

Common solar panel sizes:

Both 60-cell and 120-cell solar panels are about 3.5 feet by 5.5 feet. The difference is that 120-cell panels utilize half-cut cells, which are slightly more efficient and resistant to failure.

72-cell and 144-cell solar panels are about 3.5 feet by 6.5 feet, with 144-cell panels using half-cut cells as well.

60/120-cell panels are easier to carry and offer more flexible design options, while 72/144-cell panels cost less to install. Compare 60/120 vs. 72/144-cell panels here.

Cost/Watt

Weight

Monocrystalline (mono) solar panels are cut from a single section of silicon. They are slightly more efficient than polycrystalline (poly) solar panels, which contain cells made of blended fragments of silicon.

Mono solar panels cost a bit more than poly panels, because their increased efficiency allows you to fit more solar in a smaller space. In terms of performance, mono and poly solar panels will produce power equally well, but an array of poly panels would take up more room on your property.

Batteries

The centerpiece of off-grid solar systems. Batteries store the energy you produce. You can draw power from your battery bank to run your appliances at any time.

Off-grid solar systems use deep cycle batteries, which are designed to be discharged and recharged gradually. Typically solar batteries are sized to cover your energy usage for one night and recharge from solar during the day, completing one charge / discharge cycle over a 24 hour period.

Some common battery types used in off-grid solar applications:

Flooded Lead Acid Batteries

Flooded lead-acid (FLA) batteries are sometimes referred to as wet cell batteries because the electrolyte is in liquid form and can be accessed by removing the battery caps.

Charging flooded batteries causes water in the electrolyte solution to evaporate, so they regularly need to be refilled with distilled water to keep them topped off. This need for routine maintenance means flooded batteries are only suitable for those who have the time (and the desire) to perform maintenance checks on their battery bank on a monthly basis.

FLA batteries are especially prone to failure if not properly maintained, and we find that most people can’t (or won’t) commit to the monthly maintenance schedule needed to properly care for FLA batteries. Their strict maintenance requirements means they are not suitable for vacation homes, nor would we recommend them for full-time off-grid residences, unless you really love the idea of getting hands-on with your system.

Sealed Lead Acid Batteries

Sealed lead acid (SLA) batteries get their name because the compartment containing the electrolyte is sealed, which prevents leaks and noxious fumes coming from the battery.

Unlike flooded lead-acid (FLA) batteries, sealed batteries have minimal maintenance requirements and do not need to be installed in a ventilated battery enclosure. SLA batteries can also be mounted in any orientation, because the contents of the battery are sealed shut.

There are two sealed lead acid battery types: absorbent glass mat (AGM) and gel batteries.

• AGM batteries are less expensive and perform better than gel batteries in cold temperatures. They are also capable of higher charge and discharge rates. They are the more cost-effective sealed battery option, recommended in most off-grid solar applications.
• Gel batteries are an older technology that cost more than AGM batteries. They take longer to charge and are not as widely available as AGM. Gel batteries do perform better in high ambient temperatures, so they may make sense in hot climates, but AGM is usually the more cost-effective option.

Lithium Ion Batteries

Lithium Ion batteries tend to be about 3x the cost of SLA batteries, but they also last about 3x longer, so the higher initial cost balances out over the life of the system. (For a lifetime cost comparison chart, see the “Cost of Off-Grid Solar” section below.)

If you want a high performance battery that you don’t have to replace for a decade, lithium batteries are the most convenient option. They have faster discharge and recharge rates, weigh less and are maintenance-free. In addition, lithium batteries are modular, meaning you can start small and expand your battery bank as needed.

# of batteries

Storage Capacity

warranty

temperature range

Charging Temperature 32°F to 114°F

Discharging Temperature.4°F to 131°F

Off-Grid Inverters

The inverter is the central hub of the system, responsible for routing power between its various components. For off-grid solar, you need an inverter that is purpose-built for off-grid use.

State of the art off-grid inverters have a variety of capabilities and Smart functions. MPPT charge controllers are built in to many inverters. Some not only accept generator power inputs, but can start the generator if battery power dips too low. Inverters include the brain for monitoring systems so that you can monitor your system remotely. And if you are using lithium batteries, many inverters can communicate directly with the battery’s built in BMS (Battery Management System) in order to maintain proper charge levels and to make battery bank information available for your monitoring.

Your off-grid inverter takes low voltage DC power from the battery bank and converts it into 120/240V AC, the standard format that powers household appliances.

State of the art off-grid inverters offer several Smart features to manage your system. A few examples include remote monitoring, automatic generator start, and the capability to communicate directly with lithium battery banks to monitor and maintain proper charge levels.

Racking

The foundation that supports your solar array. We recommend the Ironridge XR metal rail system.

Racking is universal between grid-tie and off-grid systems. There’s no special equipment; it’s just a metal structure that supports the weight of the solar array.

Both roof and ground mount racking works well, and there are pros and cons to both options. Take a look at our article comparing ground mount vs. roof mount solar if you’d like help deciding where to mount your array.

Charge Controllers

A solar charge controller regulates the battery charging process. Charge controllers keep solar panels from overcharging your battery bank by regulating the voltage the panels generate.

48-volt batteries are common in off-grid systems; however, most solar panels deliver more voltage than is required to charge the batteries. Charge controllers convert the excess voltage into amps, keeping the charge voltage at an optimal level while reducing the time necessary to charge the batteries fully.

Undercharging and overcharging both reduce the expected lifespan of your battery bank, so it’s important to pick the right controller and properly program the charging profile of the batteries.

There are two main types of charge controller: PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracker).

• PWM controllers are an older technology that we do not recommend for off-grid homes. They are less efficient and have limited options for compatible solar panels. PWM controllers are better suited for less intensive applications, like remote telecom setups.
• MPPT controllers are a more efficient and reliable technology that maximizes the current running into the battery bank. As the intensity of sunlight changes throughout the day, MPPT controllers automatically adjust the voltage to charge the battery bank as efficiently as possible. We exclusively use MPPT charge controllers in our solar kits to meet the demands of full-time off-grid living.

Power Center

A power center is a pre-wired unit that contains the “brains” of the system.- the inverter, charge controllers, monitoring system, overcurrent / surge protection, AC and DC inputs/outputs, and wiring to tie it all together.

Buying a pre-wired power center, or a state of the art off-grid inverter that has most of these features built-in, saves the intricate work of correctly mounting and wiring a number of components together.

How much does it cost to go off grid with solar?

First, the standard disclaimer: every off-grid solar project is different, and your costs will vary (™). To put together a custom off-grid solar package that suits your needs, reach out to us for a free PV proposal.

However, it can be useful early in the research process to look at some sample systems to help benchmark the costs of off-grid solar. Feel free to take a look at our off-grid solar kits in our shop for up-to-date pricing.

Please note that the kits in our shop do not include the cost of batteries, as the battery bank will need to be sized to match your energy consumption (we’ll explain how to do that in the Off Grid Solar System Design section).

Tax Incentives Polices by State

You are eligible to claim the solar tax credit if:

• You owe taxes for the filing year that the system was installed
• The system is installed at your primary residence
• You are the owner of the system (leases / PPAs do not apply)

Backup Generator Costs

While solar can handle your day-to-day power needs, most off-grid systems are designed for a single day of autonomy (days that you can fully meet your energy needs with solar). You will inevitably encounter stretches of bad weather where your solar panels can’t produce enough power to cover your needs.

For that, off-grid systems must include source of backup power. For most people, that means adding a backup gas generator to get through periods of low solar production.

Be sure to budget for a backup generator as part of the overall cost of your system.

Need Help?

We’ll help you design an off-grid solar system. Whether you’re converting an existing system to off-grid or starting from scratch, we can guide you to the best energy-saving solution.

Minimizing Off-Grid System Costs

Before you size your off-grid solar system, consider whether you can take measures to reduce your energy usage. Lower consumption means you can get away with a smaller battery bank and inverter, reducing system costs.

Two simple things to consider:

• Propane Appliances Consider outfitting your off-grid home with propane appliances to limit your electricity usage. We recommend looking for a propane stove, clothes dryer, wall heater and on-demand water heater; in our experience these are more cost-effective than running them off electricity. Be sure that you have reliable access to a propane vendor near you. Some places have propane delivery services, which are convenient.
• Stagger Appliance Usage Usage Off-grid systems are designed with peak consumption in mind.- how many electrical loads are run simultaneously. By staggering your usage of major appliances, you can reduce the peak demand on your system. For example, if you’re willing to run your dishwasher and laundry at different times, that will reduce peak demand and keep system costs in check.

Off-Grid Solar System Design

Off-grid living means you are fully responsible for your own power production; if your energy storage doesn’t live up to your needs, there’s no grid power to fall back on. For that reason, it’s critical to take all the factors that impact solar production into account during the system sizing process.

Factors that Impact Off-Grid System Design

Before we get into the system sizing process, consider the following:

Sun Hours Some parts of the country get more exposure to the sun than others. You’ll need to know how many sun hours you get in your location.- a measure of the duration and intensity sunlight in your region. Fortunately there’s no guesswork involved, thanks to the solar insolation maps provided by the National Renewable Energy Laboratory (NREL). Look for the DNI (Direct Normal Irradiance) maps and take a note of the average sun hours in your location. Most places in the US fall in the range of 4-5 sun hours per day. You may notice from the monthly maps that sun hour availability dips dramatically in the winter. Your solar production will fall below your needs in the winter months, and it will be up to your generator to pick up the slack. While you could theoretically oversize your solar array so that it works in those bleak winter months, it would be insanely expensive (think triple the system costs). It’s much more cost-effective to size your solar array to be effective most of the year, but let the generator take over in the winter.

Obstructions Solar panels work best in full sunlight, so you want to keep them free from obstructions that would cast shade on the panels. Check your build site for trees, chimneys, or anything else that could block sunlight from hitting your panels. Keep in mind that shadows get longer in the winter as the sun takes a lower arc across the sky. Make sure that your build site will be free from shade all year-round. If partial shade is unavoidable, the impact can be mitigated with micro-inverters or power optimizers. However, they won’t match the output of an array built with full exposure to sunlight.

Orientation Solar panels produce the most power when they face directly toward the sun, which takes a path in the sky that follows the Equator. So if you live in the Northern Hemisphere, you want to face your panels due South. In the Southern Hemisphere, face them North. As you select a build site, make sure you can face your panels in the right direction. If you don’t have a suitable space on your rooftop, consider a ground mount away from obstructions to get the most out of your panels.

System Voltage Solar batteries come in a variety of voltages, including 6V, 12V, 24V and 48V. We recommend a 48V DC battery bank simply because it’s the most efficient and cost-effective option available. At lower voltages, you will need to buy more electronics and invest in more cabling to handle the higher amperage from the system (the amperage is doubled every time the voltage is cut in half). In an off-grid residence, 48V is the better option. For best results, it is most common to use 6V batteries and wire them in series for a total of 48 volts.

Determine Your Energy Needs

There are three key factors to consider when sizing an off-grid system:

(“KWh” stands for kilowatt-hour, the standard measure of how much electricity your appliances consume while in use. You can find this rating on the appliance’s EnergyStar sheet.)

To start, make a list of each appliance’s wattage consumption. Then write down how many hours you plan to use each appliance on a daily basis. This information is necessary to move forward with the sizing process.

off-grid load calculator

We’ve got a handy off-grid load calculator to help you keep track of your appliance’s wattage consumption.

Important! 1,000 watts = 1 kilowatt. Be sure to convert watts to kilowatts before you make your kWh calculations, or your numbers will be off!

What is Your Peak Power Demand?

What are the electrical loads that you will need to run? Will they all run at the same time, or can you rotate the loads?

Your peak power demand is your total wattage usage when you are running all the electrical loads you need simultaneously. By staggering usage of major appliances at different times, you can reduce your peak power demand and bring system costs down.

Figure out how many appliances you expect to run at the same time, and add up their wattage consumption. The total is your peak power demand. Make note of this number, as we’ll be using it to figure out your inverter size.

What is your daily kWh usage?

Using the load evaluation worksheet you filled out, multiply the appliance wattage by the number of hours it will be in use each day. As an example, if you run a 1,500-watt dishwasher for 30 minutes each day:

1,500 watts x 0.5 hours = 750 watt-hours (Wh)

Remember to divide by 1000 to convert from watts to kilowatts.

750 Wh / 1000 = 0.75 kWh daily usage

Repeat this step for each appliance you will use, and tally them all up to get your daily kWh usage. Write that number in your notes.

What is your nightly kWh usage?

In the daytime, the power you use comes straight from your solar panels. When the sun goes down and panels are no longer generating power, the battery bank takes over and your appliances will run off of stored energy.

Using the same method as above, add up the appliances you’ll use at night and tally them here. Your fridge, TV, and smartphone charger are common appliances that run in the evening and overnight. Your inverter also has a self-consumption rating (the amount of power it takes to run the inverter) which should be accounted for.

Well-designed off-grid homes can use as little as 3-4 kWh per night, but yours may be higher if you want to run power-intensive appliances in the evening, like an HVAC system.

Tally up your nightly kWh usage and write the number down in your notes.

Off-Grid Battery Bank Sizing

With the above figures in hand, we’re finally ready to begin our system sizing calculations. We’ll start with the battery bank, which needs to be sized to accommodate both peak and continuous demand.

For the purpose of demonstration, we’ll walk through the math for a sample off-grid system with the following energy needs:

TruPower AC Off Grid Residential System 3600W

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Description

TruPower AC Off Grid Residential System 3600W

Silicon Solar Off Grid Residential Solar Kit is suitable to offset a huge amount of your energy bill. The off grid system is perfect to provide power for homes in remote areas or places where blackouts and brownouts are common. The 3600 W residential kit equipped with 12 x 300W solar panels, 8 X 260AH batteries, and is enough to power most household appliances. This system does not connect to the grid power (or wall outlet), it can become your primary source of electricity and enable your home to become energy independent (depends on the size of household), which in turn saves you money from avoiding grid usage. Off-Grid Residential Kit is a perfect kit if you want to replace using energy from the electricity company or as an emergency backup in case of earthquakes or blackouts, you can have all these batteries to power your appliances such as computer, light, etc.

Off grid solar kits are easy to install, usually within a day, but Silicon Solar recommend the presence of an electrician or solar installer or at least have them verify that all installations are correct before power configuration.

This kit include all the major components needed for a solar installation. Because each installation is different, some parts may need separate purchases to satisfy your specific project needs.

30 YEAR POWER GUARANTEE Silicon Solar provide a 30 year power guarantee on the TruPower solar panels. We offer the longest power guarantee on the solar panel in the industry to assured our TruPower solar panels generation of energy, and also to assured you get the right return based on your investment.Silicon Solar TruPower Solar panel 30 years power guarantee provide a reliability which is beyond compare.

10 YEAR PRODUCT WARRANTY Silicon solar also offer a 10 year component warranty on the TruPower Series Components. By using Silicon Solar as your innovative solar solution, you can benefits from our warranty!

Please contact us or call us for more information about warranty at 1.800.786.0329.

4000W Pure Sine Wave inverter(Off-Grid)