How to Build Off Grid Solar Power System
In today’s modern world, the urgency for sustainable and renewable energy sources has reached unprecedented levels. Among the most popular and efficacious methods of generating clean energy, solar power takes center stage. By constructing an off-grid solar power system, you have the remarkable ability to harness the immense potential of the sun, generating electricity for your residence independently of the conventional power grid. Within this enlightening article, we will expertly navigate you through the intricate process of planning, designing, and seamlessly installing your very own off-grid solar power system.
Equipment and Tools Needed
Before you start the installation process, you will need to gather all the necessary equipment and tools. Here is a list of the essential items you will need:
- Solar panels: These are the energy-producing part of the system.
- Inverter: This device converts direct current (DC) from the panels into usable, alternating current (AC). Most modern appliances operate on AC power.
- Battery: This stores excess power during the day and supplies it during the night since solar panels stop working after sunset.
- Charge controller: This device improves the efficiency and safety of the battery’s charging.
- Wiring: A set of wires is needed to connect all the system components.
- Mounting racks: These are useful for placing the solar panels at an optimal angle for power production.
You may also need some miscellaneous items such as fuses/breakers, connectors, cable ties, metering devices, and terminal lugs.
For tools, you will require a wire stripper, crimping tool, pliers, screwdriver, and wrenches.
Designing the Solar Power System
Designing the solar power system involves determining the size of the system you need. This size mainly depends on the total electricity requirement of all the appliances the system will power. To do this, list all your appliances and their power (hourly) and energy (daily) consumption. The power rating of each appliance is given in watts (W), and often noted on the appliance. You can also use online tools to find out the power consumption of your appliances.
Calculate the energy consumption by multiplying power consumption by hours of use. Once you know the power rating of all appliances you plan to run on solar, make a table with power and energy values.
For example, if you have a refrigerator that consumes 150W and runs for 24 hours, the energy consumption would be 150W * 24h = 3600Wh or 3.6kWh.
Sizing the Solar Panels
To size your solar panels, begin by finding out the average sunlight hours in your location. You can find the daily sunlight hours for any location from one of the many sources on the internet. Once you have that number, you can use the following calculation to find out the solar panel size:
Total energy required (Wh) ÷ daily sunlight hours (h) = solar panel size (W)
For example, if the total energy required is 2,740 Wh and the daily sunlight hours are 4.5 h, the solar panel size would be 2,740 Wh ÷ 4.5 h = 608 W. With some safety margin, you can use two 350-watt solar panels connected in series.
Sizing the Battery and Charge Controller
Most companies now offer batteries specified in Wh or kWh. For the load profile in our example, the battery should be able to store a minimum of 2.74 kWh. Add some safety margin to this, and you can use a reliable battery size of 3 kWh.
Selecting a charge controller is similar. Look for a charge controller with a voltage rating that matches the panel and battery voltage (e.g., 12 V). Check the controller specs to ensure its current capacity is higher than the rated current of the solar panels (e.g., use a 20A controller for 11A solar panels).
Choosing the Inverter
Your inverter selection depends on the ratings of your battery and solar panel. Choose an inverter with a power rating slightly higher than your panels. In the example above, we have 750 W panels and can use a 1,000 W inverter.
Next, make sure that the inverter’s PV input voltage matches the voltage of the solar panel (e.g., 36 V), and the battery input voltage matches the voltage rating of your battery (e.g., 12 V).
You can buy an inverter with integrated ports and connect your appliances directly to the inverter for ease of use.
Choosing the Right Cable Sizes
For small systems like the one we are designing, cable size is not a big concern. You can choose to use a general, 4 mm cable for all your connections.
For larger systems, correct cable sizes are essential to ensure safe and optimum performance. In that case, make sure to use an online cable size guide.
Installing the System
By this point, you will have all the correctly sized equipment. This brings you to the final step — installation. Installing a solar power system is not complicated. Most modern equipment comes with ready-made ports and connectors, so it’s easy to connect the components.
When connecting the components, follow the wiring diagram shown below. This will ensure that the power flows in the correct sequence and direction.
Embracing solar energy doesn’t necessarily require hiring a team and spending a fortune. For a simple off-grid setup, you can take matters into your own hands with basic electrical knowledge and a dash of math.
Alternatively, you can opt for a portable solar system, which conveniently combines the battery, inverter, and other electronics into a single device. Just plug in your solar panels, albeit at a slightly higher cost, and enjoy the simplicity it offers.
The construction of an off-grid solar power system is a gratifying and eco-friendly endeavor. With careful planning, the right equipment, and a DIY spirit, you can tap into the sun’s power, generating clean and renewable energy for your humble abode.
300W Solar Panel * 4 PCS
- Model:SH-300W Rated Power (Pmax):300W
- Maximum Excitation Voltage(Vmp):32.2V
- Maximum Operating Current (Imp):9.32A
- Open-circuit voltage(Voc):38.8V
- Short-circuit current(Isc):9.71A
- Power Tolerance:±3%
- Maximum System Voltage:1000V
Solar Inverter * 1 Piece
- Built-in MPPT Controller Model :60A/24v
- LED+LCD Display
- 1. High frequency switching technology
- 2. Multiple protection technology
- 3. MPPT control technology
- 4. Battery management technology
Gel Battery * 2 PCS
- Type：Energy storage batteries
- Chemical Type：Gel Battery
- Battery cover and exhaust plug structure: Valve controlled sealed storage battery
- Status of charge: maintenance-free battery
Solar panel bracket * 1 set
- Usage: Ground
- Galvanized steel bracket has good bearing capacity, no deformation, corrosion resistance, no maintenance cost, and can carry 4*300W
- photovoltaic panels
- System configuration: 1 bracket for each system
Photovoltaic cable/battery cable*1 set
- Polyethylene TUV certified 4MM2 red and black 50m copper core photovoltaic outdoor special cable
- Application of temperature: -40℃~120℃
- Good resistance to UV, ozone and other compounds
- Good mechanical structure strength.Effectively waterproof, oil and chemical corrosion proof
MC4 connector * 1 pair
- Main Features：
- 1. Large current and high voltage bearing capacity
- 2. Good impact resistance
- 3. Low contact resistance
- 4. Innovative sealing, waterproof and dustproof design, up to IP67
- 5. Excellent high and low temperature, waterproof, UV resistance and other properties, suitable for long-term outdoor use.