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How does an RV solar system work? If you look at the solar setup in your RV and see panels, controllers, breakers, bus bars, batteries and an inverter, the entire system can seem intimidating. The good news is that it becomes much easier to understand when you follow the basic flow of electricity from one component to the next.
In this Tech Tip Tuesday, Jeremy, Solar Instructor at the National RV Training Academy, breaks down an RV solar system and explains how the major components work together. Whether your solar system came installed from the factory or was added later, understanding this basic flow can make the system much less intimidating.
How Does an RV Solar System Work in a Basic Setup?
Jeremy starts with one of the basic solar systems commonly found on RVs.
The process begins with the solar panels. From there, the power travels to an MPPT solar controller and then to the batteries.
He refers to this basic arrangement as a trickle charger system. Its purpose is to help keep a lead acid or lithium battery charged when the RV is not connected to shore power.
That is the basic concept. However, larger systems can add more components and give RV owners additional capabilities.
What Does an MPPT Solar Controller Do?
In the larger whole house inverter system, the solar panels take sunlight and convert it into DC electricity.
The electricity travels from the panels through DC breakers, which provide protection within the system. From there, the electricity reaches the MPPT solar controller.
The solar controller takes the higher voltage produced by the solar panels and steps it down to the voltage needed by the RV battery system.
He gives an example of approximately 60 volts coming from the solar panels. The MPPT controller can step that down for a common 12 volt RV battery system.
Once you understand that job, the controller becomes much less mysterious. It is another step in the flow of power between your solar panels and the rest of the system.
What Are Bus Bars in an RV Solar System?
After leaving the MPPT solar controller, the system Jeremy demonstrates connects to positive and negative bus bars.
Polarity matters.
Red represents positive, and black represents negative. Emphasizing that you do not want to connect black to the red bus bar or red to the black bus bar because that creates reverse polarity.
From the bus bars, power can travel toward other parts of the system, including the inverter and batteries.
What Does an RV Inverter Do?
The inverter is one of the most important components to understand when learning how an RV solar system works.
The inverter takes 12 volt DC electricity and converts it into 120 volt AC electricity.
Why does that matter?
The conversion allows you to operate AC appliances in your RV, including things such as an air conditioner or microwave, when your system has enough available power to support them.
Jeremy demonstrates this conversion with a multimeter.
First, he sets the meter to DC volts. Using the red lead on positive and the black lead on negative, he measures approximately 13.2 volts DC entering the inverter.
Next, he changes the multimeter to AC volts and measures the output side of the inverter. The meter shows approximately 119.7 volts AC.
That demonstration provides a simple way to see what the inverter is doing. It takes the DC power available from the battery system and turns it into AC power that can be used inside the RV.
How Can RV Solar Help With Off Grid Camping?
A larger solar, battery and inverter system can give you more options when camping away from shore power.
Jeremy gives examples such as camping near Mount Rushmore on Bureau of Land Management land or camping at the beach. With the appropriate system, you can still have access to AC power for appliances such as an air conditioner or microwave.
However, having an inverter does not mean you have unlimited power.
That brings us to another important part of understanding your RV solar system.
How Long Can You Run RV Appliances on Batteries?
This question ultimately comes down to your battery bank.
The inverter can perform its job of converting DC power into AC power, but how long you can operate your appliances depends on how much battery capacity you have available.
If you want to run an air conditioner for an extended period, for example, you need to determine how many batteries are required to support that demand.
The big question is how long you want to be off-grid and how long you want to operate your appliances.
This is where an energy audit becomes useful.
What Is an RV Energy Audit?
Jeremy describes an energy audit as a way of looking at the appliances you want to operate and converting them into watts.
From there, you can begin establishing how large your battery bank needs to be and how many batteries you need to operate those appliances for the number of hours you and your family want.
Instead of simply focusing on the inverter, the energy audit helps connect your battery bank to how you actually want to use your RV.
Understanding the Basic Flow of Your RV Solar System
An RV solar installation can look intimidating when you see all the wiring and individual components at once. Breaking the system into individual steps makes it easier to understand.
The solar panels produce DC electricity. The power travels through protection devices and the MPPT solar controller. The controller steps the voltage down for the battery system. The batteries provide stored DC power, while the inverter converts DC power into 120 volt AC power.
You can follow this flow starting at the solar panels and working toward the batteries, or start at the batteries and follow the DC power through the system.
Once you understand that basic flow, an RV solar system can become much less intimidating.
If you want to go beyond the basics, the National RV Training Academy provides hands-on RV education in Athens, Texas. Students can learn about RV electrical and solar systems and build their understanding through classroom instruction and practical training.
Explore NRVTA solar training or learn more about NRVTA RV training programs to see how you can expand your knowledge of the systems inside an RV.
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