Installation of a solar PV system is not as straightforward as you think. The installation process is easy; the hard part is knowing what size of devices you will install.
For example, a single solar panel might produce 100 kilowatts per hour. However, your home might run on more power than your panel. You will need to do the calculations of the load size to determine the size of the panels you need.
Keep reading this guide if you didn’t know some calculations are needed when installing solar PV systems.
How do you load a solar panel?
A load in the solar PV system refers to the amount of power your devices consume at home. Knowing how much load your home needs to run is helpful when determining the number of solar panels you need to install.
For example, how many solar panels do you need if your solar PV system powers a 10W phone, a 100W dishwasher, and 50W LED light bulbs? Will the solar panel sustain the added load if your load is added? These are the questions you need to ask yourself when installing a solar panel.
When calculating the load in your system, you need to know the type of load in your home. Loads can be divided into two categories;
Continuous and non-continuous
Continuous loads are measured at a specific time. Like 24hrs,7days while the individual load measures a non-continuous. You can use the measures to determine the load of your home.
Load is measured in three different metrics;
- Power in Watts (W) or kilowatts (kW)
- Current in amperes (A)
- Energy in Amperes hour or Kilowatts hour (kWh)
Before you enter into the load calculations, there are a few things you need to know;
- You need to know the size of the solar batteries you have installed in your system. If you have 12V deep cycle batteries, you need solar panels that can fully charge your solar battery.
- You cannot match the current of the solar panel to that of the load. For example, if your load amounts to 100W, you need to go overboard with your solar panels. This is because of the following reasons;
- The ratings on the solar panel are created in the lab.
- Seasons change often
- At night the solar panel does not collect any energy
- Equipment deteriorates after a single use.
- The solar panel does not store any charge. A solar battery is required for the system.
- Variations such as temperature loss may happen. Converting DC into AC might also result in some current loss.
With the information above, you can now calculate the load of the solar panel.
- To get the daily load, multiply the amps wby24hours.
Example: For a 0.6A, you find the Ah by 0.6A×24hrs= 14.4Ah
- If the load is expressed in Watts, we convert it into amps by dividing it by nominal Voltage.
- Suppose you have two loads with different ratings; you can calculate the power they consume separately and add it afterward.
- For non-continuous load, we multiply it by the number of hours it has been active.
- Once you have the load, you can then go ahead and choose the solar panels that satisfy your load.
How to install solar panels step by step
After sizing solar panels and your load, you can install your solar panel. However, you need to know the type of installation you need.
Step 1: choose an ideal location.
The solar panel should be installed in an open area on the path of direct sunlight.
Step 2: Set a scaffolding
A scaffolding ensures the panels are not damaged during installation.
Step 3: install panel mounts.
The mounts are the base of the solar panels. They should be tilted in the direction of the sun for maximum exposure.
Step 4: Install the solar panels
Installation of solar panels is not complicated once the solar panel mounts are installed. Ensure you tighten the bolts and nuts for stability.
Step 5: Wire the solar panels
To ensure the solar panel sends current to the system, you need to complete the electrical wiring. You can use MC4 connectors as they are compatible with most solar panels.
Step 6: Install a solar inverter
A solar PV system cannot run on DC. An inverter converts DC into AC. The inverter should be installed closer to the main solar panel. They can be installed either indoors or outdoor. Usually, the inverter should be placed in a cool place.
However, if you want to use a solar inverter without battery, then its better to have a hybrid type solar inverter.
Step 7: Connect the solar inverter to the solar battery
The inverter must be connected to a solar battery to fulfill its function. Use the following guide to connect the two.
Step 8: Connect the inverter to the grid system
This will help you know the power needed to run your home.
Step 9: Test the solar panels
Switch on the power and test to see if the solar panels send any current to your system. You can check this on the other control panel next to the grid system.
Common mistakes in loading a solar panel
There are a few common mistakes almost every newbie makes when going solar.
- Matching the exact energy of the solar panel and the load.
- Buying solar panels based on the price
- Not putting into consideration the temperatures and weather variations.
- Ignoring resistance felt by your solar panels.
- Assuming the solar panel works at all-time even at night.
- Using the wrong metrics
Important facts to know when installing a solar system
- Solar PV equipment deteriorates with time.
- A charge controller is an essential component of a solar PV system.
- Solar panels send power in DC form. You will therefore need an inverter in your system.
- High-quality solar batteries are a good investment.
- Installing a solar energy system will reduce your utility bills by 50%.
- How you connect your system determines how your system will work.
- Different solar kit brands work differently.
- Solar energy is not always available at all times.
The above facts are not the things that happen with your solar system. You will learn a lot from your experience with the solar PV system. Generally, a solar PV system is among the cleanest and most efficient forms of energy.
What happens if no load is connected to the solar PV system?
If there is no load connected to your solar PV system, the solar panel will continue sending more energy to the solar battery. Since no connected load consumes the charge, the battery remains full. The excess charge will have nowhere to go. If the panels keep sending more energy, the solar battery might overheat. However, if a charge controller is present, the solar battery will not overheat.
Installing a solar panel is straightforward. However, you need to know the load calculations.
The load size can determine the sizes of solar panels you need in your home. When calculating the load, consider variations caused by temperature change, weather changes, the addition of load, and the deterioration of the solar kits.
Our guide on “How do you load a solar panel” will give you a clear view of how you can calculate your load.
Eng. Matthew Joseph Nandirio is the Founder of walkingsolar.
After graduating from the University of Houston in 2002, matt started working as an electrical and electronic engineer for several multi-national solar energy companies.
He has a wide range of experiences including solar system requirement analysis, planning, maintaining, debugging and even solar device development through research.
He now shares his 20 years of expertise through his articles on the walkingsolar website.
Further, he is also the author of two books on Solar Technology, “Solar Power for Villages” and “DIY Solar System for Dummies”.