Off-grid solar systems, also known as standalone solar systems, are self-contained energy solutions designed to provide electricity in areas without access to centralized power grids or for folks like us who choose to live off the grid. Unlike grid-tied systems that rely on utility companies, off-grid systems generate electricity from sunlight, store it in batteries, and convert it into usable power for household needs.
The primary purpose of off-grid solar systems is to enable energy independence and still enjoy all the technologies of today. By harnessing the abundant energy of the sun, individuals can reduce or eliminate their dependence on fossil fuels and completely eliminate a monthly utility bill. These systems empower not only individual homeowners but remote communities and perhaps in the future entire villages, towns, and cites.
Our solar system was purchased from a company here in Canada that specializes in complete off grid solutions. We’ve broken down each component below and included additional links which cover the fine details and specs regarding that piece of the system. We will also be posting future blog posts covering the exact details of how each individual component works, the role they play in the solar system and where you can find these components yourself. We’ve taken all the work out of selecting a solar system that’s right for you
The Building Blocks of Off-Grid Solar Systems
Off-grid solar systems consist of several crucial components working in harmony to generate, store, and deliver electricity. Here’s a breakdown of the main element.
Photovoltaic solar panels capture sunlight and convert it into direct current (DC) electricity. These panels are typically mounted on rooftops or open areas to maximize sun exposure. We’ll dive deeper in additional posts of how to choose the proper size panels, orientation, and angle for optimal energy absorption based on your geographic location and seasonal changes. While there are several types of solar panels available the majority of off grid systems use either…
Monocrystalline (mono) panels: These panels offer the best efficiency and generate more power than other types. Because of their high performance, you’ll need fewer panels to power your home. Monocrystalline panels are more expensive but last 25 years or longer.
Polycrystalline (poly) panels: These panels are less expensive than mono options but offer less power and efficiency. They last up to 20 years with regular maintenance. Because of their lower performance, you’ll need more panels to meet your energy needs. Consider your available roof space, power needs, and budget when comparing mono to poly panels.
We currently have three 280W Monocrystalline solar panels for our setup. On a clear sunny day this relatively small setup can produce up to 5Kw of power. More than enough to fully charge the battery bank, run our full sized fridge, Keurig, Starlink internet, Shurflo water pump, LED projector, all the lights (ten LED ceiling pot lights) and even partially charge our Tesla Model Y.
Charge controllers regulate the flow of electricity from the solar panels to the batteries. They prevent overcharging, which can damage the batteries, and ensure efficient energy storage. Just like there are different types of solar panels there are also different charge controllers.
PWM (Pulse Width Modulation) Charge Controllers: are one of the earlier types and are suitable for basic off-grid systems. They regulate the charging process by pulsing the battery voltage, maintaining a relatively constant charging voltage. As the battery voltage increases, the controller reduces the pulse width to prevent overcharging.
MPPT (Maximum Power Point Tracking) Charge Controllers: are advanced and highly efficient, making them a popular choice for larger and more complex off-grid systems. They use advanced algorithms to track the maximum power point of the solar panels, allowing them to harvest more energy from varying solar conditions. MPPT controllers can convert excess voltage into additional current, maximizing the energy transferred to the batteries.
PWM with MPPT Functionality: some controllers combine PWM regulation with basic MPPT functionality. While not as efficient as dedicated MPPT controllers, they offer a balance between cost and performance for mid-range off-grid systems.
Diversion Load Charge Controllers: these are used in systems with excess energy that can’t be stored in the batteries. They divert surplus energy to other loads, such as water heaters or dump loads, preventing overcharging of batteries.
Lighting Charge Controllers: are designed specifically for solar lighting systems, these controllers regulate the charge and discharge of batteries powering outdoor lights. They often include features like dusk-to-dawn settings and timer controls.
Our system uses the very popular Midnite Solar Classic 150V MPPT Charge Controller. This unit is capable of not only controlling input power from solar panels but also hydro and wind. With the Midnite Classic 150 we are also able to monitor our solar system remotely over the internet using either a computer or smartphone. That’s the black component on the bottom right side of our setup below.
Energy captured by the solar panels is stored in batteries for use when the sun isn’t shining. Deep-cycle batteries, designed to discharge and recharge repeatedly, are commonly used in off-grid systems. The two main types of batteries used in off grid systems are lead-acid and lithium-ion.
The Flooded Lead-Acid: These are traditional, affordable batteries with a liquid electrolyte. They require regular maintenance and proper ventilation due to off-gassing.
Sealed Lead-Acid (AGM and Gel): These maintenance-free batteries use absorbed glass mat (AGM) or gel electrolytes. They are more expensive but offer better safety and can be placed indoors.
Lithium Iron Phosphate (LiFePO4): Known for their high cycle life, durability, and safety. They have a longer lifespan compared to lead-acid batteries and require minimal maintenance.
Lithium NMC (Nickel Manganese Cobalt): Commonly used in electric vehicles, these batteries offer high energy density and longer cycle life. They’re suitable for energy-intensive applications.
Our solar setup utilizes four 6 volt Matrix, 6V, AGM “L16” Battery 415Ah @ 20hr. They each weigh a hefty 123 pounds! Because they are AGM (absorbent glass mat) they do not off-gas and can be kept in a storage box built by my dad inside in the loft. Here they are kept at a constant temperature all year long elongating their lifespan. Our plan, once these batteries have run their lifespan (usually 10-12 years) is to switch to a much smaller, lighter lithium ion single battery pack. The main advantage of a lithium ion battery beside size and weight is that they can be drawn down to much lower voltages and therefore use much more of their power storage capacity.
An inverter plays a pivotal role in a solar system by converting the direct current (DC) electricity generated by solar panels into alternating current (AC) electricity, which is the type of power used in most household appliances and electronics. This transformation is essential because solar panels produce DC electricity, while homes and businesses primarily run on AC power from the grid.
The inverter ensures that the electricity produced by the solar panels is compatible with the electrical needs of your building. It not only converts the type of current but also regulates the voltage and frequency of the AC output to match the standards of the local power grid. This synchronization allows the solar-generated electricity to seamlessly supplement or replace the electricity drawn from the grid, depending on the demand.
We have a very robust and powerful inverter known as an inverter/charger. Our Magnum Energy MS4024PAE 4000W Pure Sine Inverter/Charger 24 Volt allows us to charge the batteries using not only the solar panels but at the flip of a switch charge the batteries using a stand-by generator. Additionally we can charge the batteries while also powering the entire cabin. Lastly, this particular inverter can output 240 volts. Meaning “if ” we ever decided we could actually power something as large as an electric dryer, stove or charge our Model Y Tesla. Currently we charge the Tesla using our level 1 mobile charger.
Some off-grid systems include backup generators fueled by propane, diesel, or other sources. These generators provide electricity during extended periods of low sunlight or high energy demand. We have two portable backup generators we use based on the situation. One 4500 watt Champion we use mainly to charge the batteries and power the cabin during some winter days when the solar panels are covered, the batteries are at a low state of charge (SOC) and we also want to charge the Tesla. The other is a smaller Generac 3000 watt generator. I use that mainly to power tools to save the solar system batteries for cabin internals only. I do have an extension cord that is run from an exterior cabin outlet to the small garage where I keep the ATV on a trickle charger.
In conclusion, off-grid solar systems offer a pathway to energy independence and sustainable living. They redefine the way we think about electricity, empowering us to take control of our energy sources and reduce our impact on the environment. As technology advances and solar energy becomes more accessible, off-grid systems are poised to play a crucial role in shaping a greener and more self-sufficient future.
You might want to check out how we saved $20,000 when buying our off grid property “Cheap off grid land for half price”
DISCLAIMER: We’re not off grid house building experts. We’re off grid house building enthusiasts. the info we share may be different in your neck of the woods to always DYOR when it comes to the rules and regulations in your area(s).