As a first-time solar PV system owner, you might have no idea why you need a solar panel and an inverter. The truth is that, for your system to function as expected, these two components should be available.
How you connect the two components determines the experience you will have with your system. For example, loose connections might cause unforeseen issues soon.
Luckily, as a person who has had my solar PV for years, I can pride myself in saying I know all the tricks and tips log as I explain the dos and don’ts of solar PV connections.
How to connect a solar panel to an existing inverter?
If you have an existing inverter in your home electrical system, then it is possible to add a solar panel to the system. Adding the solar panel might seem so straightforward. However, missing one of the basics could result in more frowns when your solar goes off on you at weird hours.
This video will give you the introductory basics of such connections.
I will then take you further deep into the details of solar PV system installation. Before we start with the connection, let’s learn how solar panels and inverters relate.
A solar panel collects solar energy from the sun during the day. It sends the collected energy into the system to be used by your appliances and light bulbs in one direction in DC form. Since most home systems run on AC, a device that can convert DC into AC is required. And that device is an inverter. Why would you need to add a solar panel to an existing inverter?
There are two reasons why you might need to connect more solar panels to your inverter.
- A solar panel does not work 100% efficiently. There will always be some variables such as weather variations that hinder the panel from collecting solar energy at its maximum.
For these reasons, National Electrical Code(NEC) allows you to have solar panels 33% larger than Inverters.
- Distributors do not permit the installation of inverters of more than 5kilowatts. If your home voltage output is larger, you can install solar panels larger than the inverters. That way, you will satisfy the distributors and satisfy your needs.
You might be worried about oversizing your inverter. However, a solar panel does not send current to an Inverter. An Inverter pulls the current it needs from the solar panel.
If the solar panel is 10kilowatts and your inverter needs 5killowatts, the inverter will only pull 5kilowatts from the solar panels.
- How many more panels can fit is in your space
If you have more space on your rooftop to add more panels, then you should add them. The maximum number that can fit on your roof is 8.
- How much more power do you need
Before adding more solar panels check your Net Energy Metering utility bill. The information on the bill will be used to calculate the additional power your home needs.
Here is a step-by-step guide on adding solar panels to an existing inverter.
Step 1: size you load
Knowing how much more power you need in your home will be beneficial in knowing how many more solar panels you need.
Step 2: Add a solar panel to the space available
Ensure the solar panels are being added on the path of sunlight exposure. If your inverter is in grid-tied system, you can use some cables provided with the solar kit.
Step 3: Adjust the settings on the control panel
Existing inverters in grid-tied systems operate from a control panel. Set the amount of amps you need your inverter to pull from the solar panels. You can also switch of the electricity grid in a way the system runs on solar a ray only.
Step 4: Start and Test panels
Start the system and check if the control panel is sending any current to your inverter.
Is an inverter necessary in a solar system?
An inverter is a small yet complicated device. Its main purpose is to convert DC into AC which is used to run appliances.
Solar panels harvest energy from the sun and send it to the solar battery in one direction as DC.
Since most appliances at a home run in AC, an inverter is incorporated into the solar PV system. The inverter converts the Direct Current into Alternating Current which is sent in different pieces in one second.
If you have appliances at home which run in AC, then you need inverters.
Before adding solar panels to an existing inverter, there are a few things you should consider;
Can you connect an inverter directly to a solar panel without a battery?
How you install your inverter depends on the type of installation you are doing.
For an off-the-grid installation, you need a solar panel, charge controller, inverter, and a solar battery. This type of installation is complicated and should be done by experts.
If you are installing a grid-tied system, you don’t need to add a solar battery. The inverter is connected directly to the grid. And since an inverter does not store any power, you cannot rely on solar energy at night.
As seen it is not a must you install a solar battery in the grid-tied system. However, if you want to lay down the expensive electricity energy, you should invest in a high-quality solar battery.
Solar batteries which are also known as deep cycle batteries come in standard voltage of 12V and 24V. If an Inverter is added to the battery, it can convert the DC into AC to power appliances which require 110V or 220V.
What are the equipment needed with an inverter?
You might have heard about inverters and wondered where you would need these devices in your home.
Basically, most appliances at home cannot run on direct current which is what our power sources produce. Instead, they run on AC. All appliances that run on AC will need an Inverter. Some of the equipment that must be used with an inverter include;
Computers are very delicate. You might use computers with the same inverters that run water pumps and dishwasher. However, to protect them from power surges and sudden power outages, it would be best if you used a special type of inverters made for computers.
Washing machines are power hungry devices. If you are running a domestic or a laundromat, you will need about 1500-3000watts of power. To avoid overloading your inverter, ensure the washing machine has it’s own power inverter.
To calculate the size of the inverter you need, add a 20% wattage on top of the washing machine wattage. For example, of your washing machine is 2000watts you will need an inverter with 2400 watts. This is found by a simple calculation;
2000 watts×1.2 =2400 watts.
Medical appliances need to remain on at all times. You should use a pure sine inverter since it is the only approved Inverter for life equipment. Do not use AIM inverter in such inverters unless approved.
Most audio appliances fail due to power surges and constant power outages. Using inverters in such systems detects the surges and protects the appliances from the damage that might be caused by power surges.
Cars use AC power to start. Since a car is a large appliance, it requires a peak power pure sine inverter. Cars require a lot of power to run. You, therefore, need an inverter of about 5000 kilowatts.
These are not the only appliances that run on inverters. Other appliances include;
- Ceiling fans
- Radio frequency interference
- Microwave ovens
- Televisions etc.
Although this appliances are used with inverters, not all inverters can be used with any appliances. Consult with your manufacturer before using an inverter with your appliances.
Inverters are some of the devices that are often assumed when installing solar PV systems. However, inverters are very important. Normally, solar panels harvest energy from the sun and send the charge in one direction in DC. Many home appliances run on AC. To facilitate these appliances, an inverter is added to the solar system.
The guide above provides you with all the information you need to know about inverters.
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”.