Solar panels are a great option to power your appliances without the noise, smell, and the expenses of running your propane generator.
12V solar panels are one of the most, if not the most, commonly used type of portable off-grid system that is found in small homes, RVs, tourist vans, and even fishing boats.
But why are they so popular? What will a 12V solar panel run, exactly?
The truth is, there’s no single right answer to this question. But don’t fret, we’re here to help you identify and select the right panel for your rig. We’ve also included how to accurately calculate how much power you need.
What Is a 12V Solar Panel?
A 12V solar panel, in a nutshell, is used to power electronic 12V devices even under worst-case conditions such as low sunlight levels, high temperatures, etc.
Such a system requires the aid of a number of devices to power efficiently and effectively. Aside from solar PV panels, these include:
A 12V system is perfect when you’re looking to power your RV appliances while on the move. And it’s quite sufficient to keep everything running.
But if even one of the above is missing, the production of energy acquired from the sun wouldn’t be as efficiently stored.
How Does a Solar System Work?
Each of the above components work together to properly feed the appliances you’d like to power. For instance, sunlight is converted into DC electricity by the 12V solar panel, which is then fed to a battery via a solar regulator.
A solar regulator, as its name implies, regulates the amount of energy that’s stored in the battery.
When the batteries are fully charged, it either stops or decreases the amount of current flowing to the battery. Doing so will make sure the battery is charged properly and won’t be damaged in the long run.
DC appliances are powered directly from the battery, so if you’re looking to power only DC appliances, you don’t necessarily need an inverter. DC powers low-voltage devices such as LED light bulbs, water pump, radio, fan, etc.
However, an inverter is necessary when you’re looking to power AC (alternate current) appliances such as refrigerators, TVs, etc.
So, What Can a 12V Solar Panel Run?
The answer to this question depends on several factors.
12V solar panels come in a variety of watts. You’ll find them in 10W, 50W, 100W, and 150W.
Let’s say, for example, you’re using a 100W 12V solar panel. The appliances you may be able to run are as follows:
- Table fan
- Wifi-to-ethernet bridge
- A couple of USB-powered hubs
- Thermoelectric coolers
- Laptop
- Music devices
- TV
- Chargers for phones, laptop, etc
You’ll have to make sure these appliances operate with 12 volts. If they’re not, you’ll need an inverter for them to work. But don’t expect some of these appliances, like the TV or table fan, to run for a whole 24 hours.
Let’s discuss how to calculate and choose the right 12V solar panel for you.
Choosing the Right 12V Solar Panel for Your RV
There are two factors you’ll need to consider when deciding which solar panel size you need: your average daily power consumption, and the capacity of your batteries.
Calculating Your Power Consumption
To choose the right 12V panel for your RV, you’ll need to know how much energy your RV appliances use each day.
List down every appliance you would like to operate with your RV solar system. Once you’ve written them down, you’ll need to find the wattage in each device.
The wattage will help you determine three things based on the number of days you’ll want to camp out.
- Size of the battery bank
- Number of panels
- Size inverter
The wattage of every appliance is normally found in the back or bottom of the device. If it’s not listed, you can use a wattage meter instead to calculate it.
Estimate each device individually before adding them together to create an overall value.
Here’s how the final list should look like:
| Appliance name | Wattage | Number of units | Total hours used per day |
| 12V LED lights | 10W | 5 | 3 hours/day |
| 12V LCD TV | 40W | 1 | 2 hours/day |
| 12V table fan | 30W | 1 | 2 hour/day |
Based on the table above, the average daily power consumption will be 5*10W*3 + 40W*2 + 30W*2 = 150W + 80W + 60W = 290W/H (watt-hours).
You can use this process with just about everything in your RV. Once you’ve estimated your approximate daily power consumption, it’ll be easy to decide which 12V solar panel size you need.
Calculating the Number of Solar Panels You Need
Before we start calculating the number of panels you’ll need, we first need to determine how many watts a 12Vsolar panel produces.
The current maximum wattage found in a single solar panel is ~150W. But when a 12V solar panel is rated as such, it’s a mere instantaneous rating given by the manufacturers in a controlled environment. This is when “perfect” conditions are met. Realistically, however, there are several factors that may affect these as per the PVUSA Test Conditions (PTC).
This includes:
- Cloud cover
- Sunlight intensity
- Relative humidity
- Heat buildup
- Wattage output per square meter
Due to real-world factors, it’s better for us to say that a 150W 12V solar panel system will give you ~125W of solar power. This figure may, of course, increase if you’re living in an area with more sunlight, like Arizona, for example.
It’s therefore wise to invest in a 12V solar panel that’s approximately 20% higher than your total daily consumption.
The Equation We’ll Use
Let’s assume that there are 5 hours of sunlight on a typical day. If you have a 150W solar panel on your RV, we’ll need to multiply this by 5 hours.
But due to the aforementioned PTC, it’s better for us to use the equation 125W*5, which will equal 625W/H.
If we refer back to the example in the table above, you’ll find that your total consumption per day is 290W. This means that a single 150W panel would be sufficient to power all the above electronic devices. That, or three 50W 12V solar panels.
But realistically, nobody has 3 appliances only in their RV. You’ll have to take all these factors into consideration to know how many panels you actually need.
Inverters That Convert 12V DC to 120V or 240V AC
If you’re using an inverter to convert 12V DC to 120V or 240V AC power to run your appliances, you’ll have to keep in mind that they draw about 10-15% more energy than what the actual device requires.
Inverters work at peak efficiency of 85-90%. For that reason, the daily consumption of an RV needs to be increased by approximately 10-15% if you added the AC devices to the list.
Battery Capacity
Although they’re less important than the size of the solar panel, the capacity of your battery also needs to be taken into consideration.
The first reason is that batteries often have a limit on its charging current. If you have a small battery, you won’t be able to utilize a big solar panel.
The limit of gel or AGM batteries equals 20% of their capacity. As a result, a typical 50Ah battery can’t be charged with more than 40A.
Energy is wasted when the battery can’t store the charge. So when you invest in a solar panel for your RV, make sure you’re buying a powerful battery that can handle the size of your solar panel.
12V Solar Panels vs. 12V Solar Blankets
If you’re looking to go solar, you’ll be met with a variety of options to choose from. Before we get into the nitty-gritty, you’ll first need to understand the difference between a solar panel and a solar blanket.
Solar Panel
There are two types of solar panels that can be found on the market: portable and fixed.
Portable Solar Panels
Portable solar panels are a great first step for beginner solar users.
These panels would be a good option if you don’t plan to travel regularly. It’s not as expensive as a fixed panel, but it can be a bit heavier and bulkier compared to its counterparts.
The biggest advantage of portable solar panels is that it provides the flexibility of where to park. You can park your RV anywhere and your portable panels will still be able to capture the sunlight by moving the panels out and away from the RV.
It also often comes with a power cable of up to 25-50 feet, which makes it easier to install anywhere we want it to be.
On the topic of installation, portable solar panels can be set up in no time. Simply mount a solar charge controller near your batteries and it’ll immediately start collecting power from the sun.
Pros
- Cost-effective
- Easily adjustable
- Easy to clean
- Doesn’t require any permanent fixtures
- Allows you to get the best possible sunlight angle
Cons
- You’ll need to set it up every time you stop
- Panels only work when you’re parked
- Occupies storage space
- Panels may get damaged or stolen
Fixed Solar Panels
If you’re looking to set and forget, fixed solar panels are your best option.
This panel is physically attached to your RV, so you can charge it while on the road. It’s typically bolted on the roof of your RV, but it may also be riveted or siliconed in place with brackets and mounting hardware. All of these are more or less permanent fixtures that can only be removed with tools.
The great thing about a fixed solar panel is that you only need to install it once. And as it’s attached to the roof of your RV, you don’t have to leave extra storage space to carry it around.
Fixed solar panels offer a more low-profile look. Because it’s kept out of the way, passersby won’t even know you have a solar system set up.
The biggest disadvantage of fixed solar panels is that you’ll need to have your RV parked directly under sunlight to get the best results. Unfortunately, this isn’t always possible in campsites.
Pros
- One time installation
- Charges constantly even when driving
- Can’t be easily stolen
Cons
- You don’t always get an ideal sunlight angle.
- Difficult to clean as you need to climb up the roof to do so.
- Permanent fixture
Solar Blankets
If you’re concerned about the space and weight of a solar panel, definitely consider getting a solar blanket instead.
Solar blankets are perfect for frequent travelers. They are more expensive than solar panels, but you get excellent quality and durability in exchange. The convenience these blankets offer is what most attracts buyers to this solar option.
You can set this blanket up anywhere. You can drape it over your trailer, hang it off your awning, or just simply lie them flat on the ground. Just like solar panels, you can set it up directly under the sun where it’s most suitable.
When it’s time to go, you’ll just have to fold the blanket and store it back in your RV. It doesn’t take as much space as solar panels and isn’t as heavy. Plus, because it’s so compact, you don’t have to reduce the amount of luggage you need just to take it with you.
Pros
- Small when folded up, making it easier to store
- High efficiency
- Can be placed anywhere
Cons
- A bit expensive
- RV needs to be parked to collect energy
Conclusion
Now is a great time to encourage everyone to go solar. Other than the advantage of decreasing our environmental footprint, we also get to save a ton of money. This is a great help, especially since the cost of electricity is drastically increasing each year.
If you already own a 12V solar panel, you’ve made the right choice.
They’re the best option for those who own RVs. As long as you have enough power, you’ll never run out of energy while out camping.