If you are considering DIY solar, starting with a small off-grid system, such as a ground mount or portable unit, is much safer and easier to manage than installing a complete rooftop or grid-coupled system.
Building small off-grid systems has become easier thanks to advances in pre-configured kits, lithium battery technology and modular inverters. These systems are perfect for grid-connected home cabins, vans, emergency backups, or supplementary power. Recent growth of plug and play solar kits Integrated solar generator Off-grid setups have been made even more accessible for beginners. And, as mentioned in a previous article, many states have restricted residents from connecting their DIY systems to the power grid. With the right tools, simple energy usage calculations, and basic electrical knowledge (or by using a beginner’s solar kit), you can successfully build a small off-grid system. However, it is important to follow safety guidelines and consult local regulations to avoid danger and compliance issues.
In most jurisdictions, connecting the solar system to an electrical grid requires permits, inspections and installation to comply with building codes and utility interconnect standards. However, some states allow simplified plug-and-play grid-coupled systems or community solar participation as entry points for low barriers for homeowners.
Let’s show you how to plan, design and install an off-grid solar system.
Equipment and tools needed for DIY solar systems
Before we talk about installation, here is a list of the equipment and tools you will need.
- Solar Panel: The first and obvious item you need is the solar panel. The panel is the energy production part of the system.
- inverter: The inverter converts current (DC) directly from the panel into alternating current (AC) that can be used. Most modern appliances will run on AC power unless you choose to use a set of DC appliances for your system.
- battery: The battery stores excess power during the day and supplies it at night. This is an important task as the solar panels stop working after sunset.
- Charge controller: The charging controller improves battery charging efficiency and safety.
- wiring: A set of wires is required to connect all system components.
- Mounting Rack: Optional, but mounting racks help you place solar panels at an optimal angle for power production.
- Other items: In addition to the important items mentioned above, you may need the following components to complete the system:
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- Fuse/Breaker
- Connectors (Note that many modern components come with integrated connectors)
- Cable tie
- Metering Device (Optional)
- Terminal lug
- tool: Additionally, you will need easy-to-use tools to install your system.
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- Wire stripper
- Crimping tool
- pliers
- driver
- Wrench
How to design a solar power generation system
Designing a solar power system means determining the size of the system you need. This size depends primarily on the total power requirements of all appliances that the system supplies power.
To do this, list all appliances and their power (hourly) and energy (daily) consumption. Power ratings for each appliance are given in Watts (W) and are often listed on the appliance. You can do it too Use online tools To find the appliance’s power consumption.
Energy consumption is calculated by multiplying the power consumption for the time spent. Once you know the power ratings for all appliances you plan to run in solar, you’ll create a table with power and energy value.
This is the sample table. Note that the value in the last column is the product of the previous two columns (watts and time).
The above table shows that at any time of the day, the maximum power draw from the solar panel is 470 W, and the total energy consumed over a 24-hour cycle is 2,740 WH, or 2.74 kilowatt-hours (kWh). Let’s take a look at how you can use these numbers to calculate the size of your solar panel, inverter, and battery. Start with the battery.
Solar panel sizing
To size solar panels, start by finding the average sunlight time for your location. You can find daily sunlight time anywhere from any of the many people Information sources on the Internet. Once that numbered, here’s a simple calculation to find the solar panel size.
Total energy required (WH) ÷ Daily sunlight time (H) = Solar panel size (W)
Assuming that the above example position receives about 4.5 hours of sunlight every day, we are:
2,740 WH ÷ 4.5 H = 608 W panel
Again, with some safety margin, two 350 watt solar panels are available. These two panels are connected in series as shown below:
Battery and Charge Controller Sizing
Today, most companies offer WH or KWH designated batteries. For the load profile in the example above, the battery should be able to store a minimum of 2.74 kWh. Adding a safety margin to this will allow you to use a reliable battery size of 3 kWh.
The same goes for choosing a charge controller. Find a charge controller with a voltage rating that matches the voltage on the panel and battery (e.g. 12 V). Check the controller specifications to ensure that the current capacity is higher than the solar panel’s rated current (for example, use a 20A controller for an 11A solar panel).
Inverter selection
The choice of inverter depends on the evaluation of the battery and solar panels. Choose an inverter with a slightly higher power rating than the panel. In the example above, there is a 750 W panel and you can use a 1,000 W inverter.
Next, make sure that the inverter’s PV input voltage matches the solar panel voltage (e.g. 36 V) and the battery input voltage matches the battery voltage rating (e.g. 12 V).
You can purchase an inverter with integrated ports and connect the appliance directly to the inverter for ease of use.
Choose the appropriate cable size
For small systems like those you’re designing, cable size is not a big concern. You can choose to use a typical 4mm cable for all connections.
For larger systems, the correct cable size is essential to ensure safe and optimal performance. If so, please use online Cable size guide.
Installing the system
By this point, all the equipment is of the exact size. This will result in the final step – installation. Installing a solar power system is not complicated. Most modern equipment comes with ready-made ports and connectors, making it easy to connect components.
When connecting components, follow the wiring diagram below. This will allow the power to flow in the correct sequence and direction.
Final Thoughts
Going to solar doesn’t mean you have to hire a team and spend thousands. If you have a simple, small off-grid unit installed, you can do it yourself with a little math and basic electrical knowledge.
Alternatively, you can choose a portable solar system that uses devices that combine batteries, inverters, and other electronic devices into one unit. All you need to do is plug the solar panel into it. This option is slightly more expensive, but the easiest.
Editor’s Note: This article, originally published on February 14, 2023, was updated in May 2025.
