Solar Power For Campers: How Many Watts Needed?

Solar panels are rated for their max efficiency—that is, a 100-watt solar panel will produce 100 watts in perfect conditions. (And unless you're the luckiest camper in the world or have discovered a way to control the weather, we guarantee you won't always have perfect conditions.)

The weather, temperature, time of day, and other factors influence the amount of power solar panels actually generate. There are multiple online calculators available that take your geographic location, the time of year, etc. into account and provide the average usable hours of sunlight you can expect.

The general rule of thumb is that a 100-watt solar panel can produce about 30 amp-hours per day, so you can use this guideline to determine about how many panels you need.

Another suggestion is to match your battery capacity in amp-hours with your solar output in watts. A 300 amp-hour camper battery, for instance, would need around 300 watts of solar power. Also, keep in mind that solar panels experience a 75-90% drop in efficiency on cloudy days, so it's good to have slightly more than you need when it comes to solar power (about a 20% cushion, if possible, to account for less-than-ideal conditions).

How much solar power do I need for my RV?

Solar power is a great way to keep your RV batteries charged without the constant drain of fuel or electricity. But how many watts of solar power do you need to keep your RV running smoothly?

The number of watts you need depends on your power consumption, the type of solar panel, and the amount of sunlight available.

Power Consumption

First, you need to calculate your power consumption. This is the total wattage of all the appliances and devices you plan to use in your RV.

You can find the wattage requirements of your appliances and devices on the label. If the label only lists amps, multiply the amps by the voltage to get watts.

For example, a 120-volt hair dryer that draws 13 amps would consume about 1,600 watts (120 x 13 = 1,560).

Once you know the wattage of each device, you need to calculate how many hours you typically use each device per day. Then, multiply the wattage by the number of hours to get watt-hours.

For example, if you use the hair dryer for 5 minutes each morning (0.1 hours), you would use about 160 watt-hours each day (1,600 watts x 0.1 hours = 160 watt-hours).

Add up the watt-hours for all your devices to get your total daily power consumption.

Solar Panel Type and Output

Next, you need to consider the type and output of the solar panel.

Solar panels for RVs typically capture between 100 watts and 400 watts of solar power during peak sunlight hours. A 400-watt solar panel provides approximately 400 watts per hour of energy for every hour of peak sunlight.

However, the actual energy output of a solar panel will depend on various factors, such as the weather, time of year, and location. A good rule of thumb is that a 100-watt solar panel will generate about 30 amp-hours (approximately 350 watt-hours) per day.

Peak Sun Hours

Peak sun hours refer to the amount of sunlight a particular location receives. A single peak sun hour is reached when the sun's intensity averages 1,000 watts of photovoltaic power per square meter.

You can use resources like the Global Solar Atlas to find out the average peak sunlight hours for your location.

Calculating the Number of Solar Panels

To calculate the number of solar panels you need, divide your total daily power consumption by the watt-hours generated by each solar panel.

For example, if your daily power consumption is 1,755 watt-hours and each solar panel generates 350 watt-hours per day, you would need at least five 100-watt solar panels (1,755 / 350 = 5).

Other Things to Consider

When deciding how many solar panels to install on your RV, there are a few other factors to consider:

• Budget: Solar panels and installation can be expensive, so make sure to set a budget and choose a system that fits within your price range.
• Roof/Exterior Space: Measure your RV's roof and exterior space to determine how many solar panels you can fit.
• Permanent or Portable Setup: Portable solar panels are lightweight and flexible, making them easy to store and place anywhere. Permanent setups, on the other hand, require careful planning and installation but can collect solar power even when you're on the road.

By considering your power consumption, budget, and available space, you can choose the right number and type of solar panels to meet your RV's energy needs.

How many solar panels do I need for my RV?

The number of solar panels you need for your RV depends on several factors, including your power consumption, the solar panel's output rating, and the number of peak sun hours in your location.

First, you need to calculate your total power consumption. You can do this by identifying the wattage requirements of your appliances and devices. Then, convert volts/amps to watts if your appliance's power requirements are in volts or amps. Next, count the running watts of your appliances and add them up. After that, factor in the starting watt requirements by identifying the appliance with the highest starting wattage and adding that to the running wattage total. Finally, calculate the sum, which will give you the total starting watts you need.

Once you know your total power consumption, you can determine the number of solar panels you need based on the solar panel's output rating. A 400-watt solar panel, for example, provides approximately 400 watts per hour of energy for every hour of peak sunlight. So, if you receive 7 hours of peak sunlight per day and your daily consumption is 5,000 watts, you would need at least two 400W solar panels to power your RV.

It's important to keep in mind that environmental factors, such as temperature, can affect a solar panel's output. Additionally, it's unlikely that you'll receive 7 hours of peak sunlight each day, especially on overcast or rainy days.

When choosing solar panels, you should also consider the type of panel, your budget, your RV's roof space, and available outdoor surface area. Monocrystalline panels are the most efficient but also the most expensive. Polycrystalline panels are a middle-of-the-road option, while thin-film flexible solar panels are lightweight and portable but have the shortest lifespan and lowest efficiency.

In summary, to determine the number of solar panels you need for your RV, calculate your total power consumption and then consider the solar panel's output rating, environmental factors, and other factors such as budget and space constraints.

How do I calculate how many solar panels I need for my RV?

The number of solar panels you need for your RV depends on your power consumption, the amount of sunlight available in your location, and the solar panel’s output rating.

Power Consumption

First, you need to calculate your total power consumption. This will depend on the appliances and devices you want to run and their starting and running wattage requirements.

The easiest way to calculate your power consumption is to use a battery monitor, like the Victron BMV-712, to keep track of your battery bank charge status and your amp-hour consumption over 24 hours.

Multiply your amp-hour consumption by your battery voltage (usually 12.6V for lead-acid or 13V for lithium) to get your watt-hour power consumption.

For example, if you used 135 amp-hours from your lithium battery bank over 24 hours, your power consumption would be about 1,755 watt-hours (135 amp-hours X 13 volts = 1,755 watt-hours).

Sunlight Availability

Next, you need to determine how much sunlight is available in your location. A single peak sun hour is reached when the sun’s intensity averages 1,000 watts of photovoltaic power per square meter.

You can use the Global Solar Atlas to find out the average peak sunlight by location worldwide.

Solar Panel Output Rating

Finally, you need to consider the power rating of your panel. Solar panels suitable for RVs generally capture between 100w and 400w of solar power during peak sunlight hours.

A 400-watt solar panel provides approximately 400 watts per hour of energy for every hour of peak sunlight.

Let’s say you receive 7 hours of peak sunlight hours. Assuming the panel has an output rating of 400 watts per hour, each panel can generate 2,800 watts per day.

If your daily consumption energy is 5,000 watts, you’ll need at least two 400W solar panels to power your RV’s appliances and devices.

Other Things to Consider When Going Solar

Solar Panel Type

When space is limited, the best choice is to go for the most efficient panels to produce the maximum energy per square foot. Monocrystalline panels are the most efficient in terms of capturing sunlight.

Polycrystalline panels are a middle-of-the-road choice that costs less but offers less efficiency than monocrystalline panels.

Thin film flexible solar panels are lightweight and can be installed just about anywhere, but they have the shortest lifespan and the lowest efficiency.

Budget

A fully off-grid solar setup requires a substantial initial investment, but it can save you money in the long run. You’ll no longer have to pay to stay at campsites with shore power.

Available Space

A standard RV is 20 to 25 feet long, and the total exterior square footage is about 120 sq. ft.

But that doesn’t mean every inch is available for solar panels. Satellite dishes and other devices can eat into your surface area significantly.

Make sure to carefully map up an installation plan before purchasing your panels. Your available space will also determine how efficient your panels need to be.

What type of solar panel is best for my RV?

When it comes to choosing the best solar panel setup for your RV, there are several factors to consider. Here are some key points to help you make an informed decision:

Solar Panel Type: Monocrystalline or Polycrystalline

The type of solar panel you choose will impact its efficiency and performance. Monocrystalline silicon panels are made with a single crystal panel, allowing electricity to move through it more easily. Polycrystalline panels, on the other hand, are made from multiple crystal fragments, making them slightly less efficient. Monocrystalline panels are usually more expensive but offer better performance.

Rigid or Flexible Panels

Rigid panels are ideal for flat-topped RVs and offer durability and weather resistance. They are also more efficient in energy production. Flexible panels, on the other hand, are perfect for curved or uneven rooftops as they can conform to the surface. They are lightweight and easier to install but may have slightly lower efficiency.

Portable or Mounted Panels

Portable solar panels offer flexibility and can be set up on the ground or angled towards the sunniest spots. They are compact, easy to store, and often have integrated kickstands and handles. However, they need to be set up and taken down each time you move campsites. Mounted panels, on the other hand, are permanently installed on your RV's roof and can capture energy while you drive. They require careful installation and roof measurements to ensure they fit properly. Mounted panels also need to be parked in a way that maximizes sun exposure.

Wattage and Efficiency

The wattage specification of a solar panel indicates the amount of power it can produce in one hour. For RVs and campers, a 100- to 500-watt solar panel setup is typically sufficient to power appliances and electronic devices for a full day. If you have an electric stove or a large fridge, consider using panels that can bring in at least 400 watts. Additionally, aim for a system that produces at least two to three times your daily power consumption if you expect to use electricity around the clock. The efficiency rate of a solar panel estimates its capacity to convert sunlight into usable electricity, with the best panels operating at 23% or higher.

Budget and Space Constraints

Consider your budget and the amount of space available on your RV's roof when making your decision. Solar panels can range from a few hundred to a few thousand dollars, depending on the type and number of panels you need. Additionally, keep in mind that you may require additional equipment such as charge controllers, battery upgrades, and mounting hardware, which can add to the overall cost.

In summary, the best solar panel for your RV will depend on your specific needs, budget, and space constraints. Consider the type of panel, portability, wattage, efficiency, and installation process when making your decision. Remember to calculate your power requirements accurately and choose a setup that meets or exceeds those needs.

Should I get a permanent or portable solar setup for my RV?

When it comes to powering your RV with solar energy, you have two main options: a permanent setup or a portable one. Both have their advantages and disadvantages, and the right choice for you will depend on your specific needs and travel style.

Permanent Solar Setup

A permanent solar setup for your RV involves mounting solar panels directly onto the roof of your vehicle. This option offers a more streamlined and low-maintenance solution, as you won't need to assemble and disassemble the panels each time you change campsites. A permanent setup is also a good choice if you want to avoid the hassle and potential expense of hiring someone to install a portable system.

However, one drawback of a permanent setup is that it requires careful consideration of your RV's roof space. Solar panels are quite large, and RV roofs are typically small. So, before opting for a permanent setup, you'll need to ensure you have sufficient roof space to generate the power you need. Additionally, with a permanent setup, you'll need to park your RV in a way that maximizes sun exposure, which can be challenging if you're camping in a shady area.

Portable Solar Setup

A portable solar setup, on the other hand, offers greater flexibility. You can place the panels on the ground at your campsite, allowing you to maximize sun exposure even if your RV is parked in the shade. Portable systems are also a good choice if you have limited roof space or frequently travel to different campsites.

However, one of the main drawbacks of a portable solar setup is the assembly and disassembly required each time you move to a new campsite. This can be time-consuming and cumbersome, especially if you travel frequently. Additionally, portable systems may require additional expenses for mounting hardware and other components.

In conclusion, both permanent and portable solar setups have their advantages and considerations. A permanent setup offers a more streamlined and low-maintenance solution, while a portable setup provides greater flexibility in terms of sun exposure and campsite changes. When making your decision, carefully consider your travel style, power needs, budget, and the amount of time you want to spend setting up and dismantling your solar system.

Frequently asked questions