What Is Off Grid Solar System: Everything You Need to Know
Thinking about breaking free from the traditional power grid? If you are planning a remote cabin, embracing vanlife, or getting ready for emergencies, an off-grid solar system can help you take control of your own energy supply. But what does it really mean to live off the grid with solar power? How does it compare to a regular solar setup? And how do you make sure you choose a system that truly fits your needs?
In this guide, you will find everything you need to know about off-grid solar. We will cover how it works, what equipment you will need, what kind of budget to expect, and how to figure out the right size for your lifestyle. By the end, you will feel ready to power your home, cabin, or adventure vehicle with confidence.
What Is Off Grid Solar Power System?
An off-grid solar system, also called a standalone system, is a solar power setup that works completely independently from the main utility grid. That means you're generating, storing, and using your own electricity—no monthly bills, no grid failures, no connection to the power company.
How is it different from an on-grid system? Off-grid systems require batteries to store excess power for nighttime or cloudy days, while on-grid systems are connected to utility and often feed extra energy back to the grid (net metering).
Off-grid setups are essential for rural homes, tiny houses, remote cabins, or mobile adventures where grid power isn’t available or simply isn’t reliable.
Components of an Off-Grid Solar System
To work seamlessly day and night, every off grid solar system needs a few key parts. Unlike grid-tied setups, this system must produce and store enough electricity to meet your needs without backup from the grid. Key components include:
Solar Panels: Capture sunlight and convert it into electricity. Choose the high-efficiency solar panel if you have limited space.
Charge Controller: Regulates the flow of electricity from the panels to the battery to prevent overcharging or damage.
Battery Bank: Stores power for use at night, on rainy days, or during emergencies. Lithium-ion is most efficient, but AGM and lead-acid are budget-friendly.
Inverter: Converts stored DC power into AC power, so you can run regular home appliances.
Mounting and Wiring Kits: These hold your panels securely and connect everything together safely.
How to Decide the Size of an Off-Grid Solar Power System?
Choosing the right size off grid solar system isn’t guesswork. It’s a careful calculation based on your actual power usage and available sunlight. Here is a detailed instruction:
Step 1. Determine Your Energy Consumption
First, you need to know how much energy you need. Make a list of all the devices and appliances you want to run on solar power, such as lights, a refrigerator, fans, or any power tools. For each item, note the following:
Wattage: The power each device consumes (typically listed on the product label).
Daily Usage: How many hours per day the device is used.
Then, calculate the consumed energy by each device using this formula:
watts x hours = daily watt-hours
For example, if a 10W light runs for 5 hours, it uses 50Wh per day (10W x 5 hours = 50Wh).
Once you've calculated the daily energy usage for each device, add them all together. Then you will get your total daily energy consumption in watt-hours or kilowatt-hours (kWh). Typically, a large house in the UK may consume more than 20 kWh of energy each day.
Step 2. Evaluate Your Location and Peak Sun Hours
The amount of sunlight your area receives can vary greatly across the UK. To estimate the solar energy your system can harness, use the average annual peak sun hours for different regions:
South England: 3 to 3.5 hours
Midlands: 2.8 to 3.2 hours
Northern England: 2.7 to 3 hours
Scotland: 2.5 to 2.8 hours
Step 3. Calculate the Right Solar Panel Wattage
Once you know your total daily energy consumption and the average daily sunlight hours, you can calculate the solar panel wattage. Divide your total daily energy consumption by the average daily sunlight hours in your location:
Required Solar Panel Wattage=Total Daily Energy Consumption (Wh)/Average Sunlight Hours (hrs)
For example, if your daily energy consumption is 20kWh and you live in an area that gets 4 hours of sunlight per day:
Required Solar Panel Wattage = 20kWh/4hrs = 5kW
This means you need a solar panel system with at least 5kW capacity to meet your daily energy needs.
Step 4. Get the Number of Panels
Now you can figure out how many panels you’ll need. Use this simple formula:
Number of Panels = Required Solar Panel Wattage / Solar Panel Wattage per Panel.
For example, if your system needs 5kW and each panel is 300W:
5000W / 300W = 16.67 panels.
You would round up to 17 panels. Always allow a little extra capacity to handle cloudy days and system inefficiencies.
Step 5. Determine Battery Storage Capacity
For reliable off-grid living, a 5kW solar system aims for a battery bank that holds between 15kWh to 20kWh of energy. Choosing a 15–20kWh battery gives you strong coverage for everyday use and unexpected cloudy days.
Step 6. Sizing the Inverter
Your inverter must handle both your regular and peak loads. First, add up the wattages of devices you expect to run at the same time. Then pick an inverter with a continuous output higher than that total. For appliances with motors, like fridges or pumps, allow for 2 to 3 times their rated power for start-up.
For example, if your running load is 4000W and motor surge adds 3000W, your inverter should handle 7000W at peak.
How Much Does an Off-Grid Solar System Cost?
The cost of an off-grid solar system in the UK varies significantly based on factors such as energy consumption, system size, battery storage capacity, and installation complexity. Generally, a typical off-grid solar system for a UK household with moderate energy consumption usually costs between £10,000 and £20,000. Here’s a simple table listing the main components and their typical costs:
Component | Typical Price Range | Description |
Solar Panels | £1,000 – £2,000 | Covers around 5kW capacity, usually 20 panels at £50–£100 each |
Battery Storage (LiFePO4) | £3,000 – £6,000 | 10–15kWh storage to support daily use and night-time supply |
Inverter and Charge Controller | £1,000 – £1,900 | Includes both the power inverter (£800–£1,500) and a solar charge controller (£200–£400) |
Installation & Labour | £1,500 – £3,000 | Varies depending on system size and local installer rates |
Optional Generator | £1,000 – £2,500 | Backup power source for extended cloudy periods or winter use |
Wiring and Mounting Gear | £1,000 – £1,500 | Includes cables, brackets, connectors, and protective hardware |
Explore EcoFlow Off-Grid Power Solutions for Homes and Adventures
If you're looking for a more streamlined way to set up off-grid power, modular systems like the EcoFlow DELTA Pro Portable Power Station offer a flexible alternative to traditional setups. Instead of sourcing separate panels, batteries, and inverters, DELTA Pro gives you a complete, scalable solution that’s easy to use and powerful enough for home or travel. Here’s what makes it stand out:
Expandable Capacity: Starts at 3.6kWh and scales up to 25kWh for longer backup or full off-grid living
1600W Solar Input: Recharge quickly with portable or fixed solar panels (11–150V, 15A)
Massive AC Output: 3600W standard, expandable to 7200W, enough for most household and outdoor appliances
LFP Battery Technology: Over 6,500 cycles, offering up to 10 years of use
Conclusion
Living off-grid is no longer just a dream; it’s a realistic and rewarding way to power your life independently. With the right off grid solar system, you can enjoy clean, quiet, and consistent power wherever you are, whether it's a mountain cabin, a coastal cottage, or your camper van.
Understanding your energy needs, choosing the right components, and investing in quality gear, like EcoFlow off grid power solutions, will ensure you have power when you need it most. With smart planning, going off-grid can be both practical and empowering.
FAQs
What does an off-grid solar power system mean?
An off-grid solar power system is completely independent of the utility grid. It uses solar panels to generate electricity and stores it in batteries for use anytime, even at night or during cloudy weather.
What is the difference between on-grid and off-grid solar?
On-grid systems are connected to the public power grid. Off-grid systems are standalone and don’t rely on the grid at all. Off-grid requires batteries to store power, while on-grid may use the grid for backup.
What are the disadvantages of an off-grid solar system?
The main downsides are higher upfront costs, the need for batteries, and limited power if sunlight is low for days. It also requires careful energy planning and monitoring.
How many kW is an off-grid solar system?
The size of an off-grid solar system typically ranges from 3kW to 10kW, depending on your daily energy usage and backup needs. Smaller setups (3–5kW) suit cabins or small homes, while larger systems (6–10kW or more) are ideal for full-time off-grid living in larger households.