Should RV Solar Panels be in Series or Parallel?

Getting solar panels for your RV is a smart choice, but when stepping into the world of solar panels, it’s easy to feel bogged down by questions. If you’re not an expert electrician, you might find yourself wondering, what are series and parallel circuits, and which one works best for RV solar panels?

Solar panels that are wired in PARALLEL generate more power without going past voltage limits and the circuit won’t break even if one of them stops working. However, parallel wiring might blow fuses if the amperage gets too high. Series and parallel wiring can both be utilized to maximize power generation without blowing any fuses.

Series and parallel wiring both have different pros and cons, and it might be best to learn more about each before deciding on which system you want to use for your RV.

Circuit Basics: Series and Parallel

Before we can get into the pros and cons of each, it’s important to step back and understand what exactly parallel and series circuits mean. I’m sure you understand that they’re different electrical wiring systems, but what exactly does each mean?

Series and parallel wirings are both different types of circuits. Before we get into the types of circuits, you first need to understand voltage, current, and circuits. I’m sure you’ve heard those terms before, and they actually mean very specific things in terms of electricity. If you still remember what all this means from your high school physics class, then feel free to skip this part. If not, get ready to learn the very basics of how electricity works.

Circuits are closed loops that allow for the flow of electricity. Electrons travel through circuits, and circuits must be connected in closed loops, or the electrons won’t have anywhere to go. If circuits are broken (if the loop is stopped because an element stops working, or if the wires aren’t connected anymore), then the electricity will stop flowing.

Voltage is the electromagnetic force that pushes the electrons along in the circuit. Voltage is measured in Volts (V). It is also called “electric potential” due to its similarities to potential energy. But you don’t need to be a voltage expert; just know that voltage is the force that pushes the electrons through the wires.

Current is the rate at which electrons flow through the circuit. In this way, current is very similar to the concept of water currents. The faster the electrons are flowing through the circuit, the higher the current. Current is measured in amps, and it will sometimes be referred to as “Amps” or “Amperage.” Don’t let those strange words confuse you; if someone says “amps” or “amperages,” just remember that they’re talking about the current.

These two elements work together to explain how circuits run. If a battery is connected to a loop of wire and a lightbulb, the battery provides voltage to push the electrons through the lightbulbs, therefore creating current and making the bulbs light up.

Below is an image of each type of wiring system in its simplest form. The image uses lightbulbs but you can just imagine each lightbulb representing an individual solar panel:

As shown above, when an electrical circuit is in series, the elements are connected to each other directly, so that the current will flow through all of them in series. There is only one path for the electrons to follow, so they will go through all connected lightbulbs, or solar panels, in order to complete the circuit and finish the loop. Electrons love traveling in loops, and anything that breaks the loop will keep them from traveling at all. So if one of the lightbulbs burns out in a series circuit, the entire circuit will stop, since the electron’s only path to travel has been effectively broken.

This also means that in series circuits, the current stays the same throughout the entire circuit. The electrons are restricted to one path, so the flow rate of that path isn’t going to change depending on where in the circuit an electron is. If the first lightbulb has a current of 1 amp going through it, the second lightbulb will as well.

But this also means that the voltage is going to be different for each element in the circuit. The voltage, in essence, is being used up by each lightbulb, because the battery has to push the electrons through each lightbulb. In series circuits, voltage changes.

Parallel circuits work very differently. In the parallel circuit shown above, you can see that the circuit breaks off into two paths, meaning that the electrons aren’t limited to one method of travel. They can go into either lightbulb and then return to the battery, just to do it all over again. They don’t have to travel through both lightbulbs; in fact, they can’t. In this way, each lightbulb acts as its own little circuit, they just so happen to be connected to the same power source.

If one of the lightbulbs burn in a parallel circuit, it won’t break the circuit, and the other lightbulb will continue to function properly. This is why most Christmas lights are wired in parallel nowadays. If one little red bulb burns out, it doesn’t matter, because the rest of it will continue to brighten up your house, and Christmas carolers will be none the wiser.

This means that in parallel circuits, the voltage will stay the same throughout the circuits because the voltage only has to push each individual electron through one lightbulb (instead of two, like in series). But the current will be different for each lightbulb since the current breaks off into two paths, and it might take longer for the electrons in one path to get through their lightbulb than it does on the other path.

Electricity and electrical currents are super difficult to understand, so don’t feel bad if it doesn’t all click right away. There’s a reason that plenty of people hated their physics classes. To simplify, here’s the only stuff you need to remember about circuits in order to understand the pros and cons of each for solar panels:

  • In a series circuit, if one element breaks, the entire circuit will stop working.
  • In a series circuit, the voltage adds up for each element.
  • In a parallel circuit, the amps (current) add up for each element.

Pros and Cons for Solar Panels

Solar panels are connected in a circuit in order to run effectively. Unlike the lightbulb example from above, the solar panels are instead connected to an inverter and a charger. So instead of a battery pushing voltage through the solar panels to provide power, the solar panels will be collecting power from the sun and pushing electrons through the wires, charging up the charging battery (or grid) with power to be used in your RV.

Solar panels aren’t using up energy from batteries; they’re providing the energy, which means different things for parallel and series circuits.

If solar panels are wired in parallel, then the principle that the current adds up will hold true. This is a huge oversimplification, but more amps (faster current) mean more power overall, and the solar panels will produce more power in less time than it would take for solar panels wired in series to produce the same amount of power.

However, this also means that the solar panels might produce more power and amps than the charger and inverter can handle. Almost all electronic devices have fuses inside of them, which are little devices that will “blow” (usually melt) if the current gets too high. This is to prevent too many amps from running through them and ruining the entire device.

Wiring them in parallel also means that if one of the solar panels stops functioning properly (for whatever reason), the rest of the solar panels will keep on functioning just fine since the circuit won’t be broken. If you’re on a road trip and one of them is broken, you’ll still have plenty of power and you’ll be able to keep going just fine.

If you want to know more about how parallel-wired solar panels work, Click Here to read an article that goes into greater detail.

Solar panels wired in series will not blow out a fuse…but they’ll go out like Christmas lights if one of them breaks. If the RV happens to hit a pothole that jostles even one of the solar panels, then all of the solar panels will stop functioning. If one goes down, they all go down, like dominos. This is a worst-case scenario, so it might not happen, but technology doesn’t always work the way we expect it to, and it would suck to be out on a road trip when all of your power suddenly stops working.

For this reason, it is the recommendation of many people that you should wire your solar panels in parallel. When it comes down to it, parallel has a higher power output, and the entire system of solar panels won’t be rendered useless if one of them stops working for some reason.

However, each case is different, and it is important to consult the professionals who are selling you your solar panels, as well as your electrician to know what method of wiring is right for you. Some people prefer solar panel circuits that are combinations of series and parallel wiring, and a professional can tell you exactly what each circuit system means for your solar panels and RV.

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