We live in our RV full-time and have invested in a solar system that allows us to run our air conditioner and many other appliances completely on solar power. Below we’ll share what we’ve learned from a combination of experience and research about how much solar you need to run an RV AC unit.
The Basics of Solar Power
Let’s go over a few fundamentals that are critical to calculating how much solar you’ll need to power an AC using only solar power. It is important to first look at the basics of how solar power works and the formulas and calculations you can use to determine what components you might need.
If you’re already familiar with the basics of solar power or have read the sister article to this on how much solar you need to run an RV fridge, jump here for calculations and recommendations for running your RV AC on solar power.
What is Solar Power?
Solar power is exactly how it sounds; harvesting energy from the sun and storing it in batteries to use immediately or at a later time (over night).
You’ll typically have an inverter for your RV that turns the power in your battery bank from a lower voltage (12v, 24v, 48v) to 120 volts to power household appliances.
To know how much solar you need to power an RV AC and any other appliances you’re interested in, first you need to understand a bit about electricity, which we dive into next!
Watts, Volts, and Amps
To figure out how much solar you need to run an RV air conditioner, you first need to understand watts, volts, and amps.
To grasp the basics, try thinking of electricity as water flowing through a pipe. Watts (W) represent the power or energy used, which you can think of as the overall volume or amount of water moving through the pipe. Volts (V) measure the electrical pressure, which you can think of as the water pressure, and amps (A) indicate the rate of electrical flow, or how fast the water in the pipe is moving.
- Watts (W): Watts represent the amount of electrical power consumed or produced by an appliance. In our case, it signifies the energy required to run an RV AC. Typically, an conventional RV AC consumes around 1000-1800 watts of electricity when running. This value can vary depending on the size, efficiency, and specific features of your AC unit.
- Volts (V): Volts refer to the electrical pressure that determines how forcefully electricity flows through the system. Most RVs operate on a 12-volt system, but your air conditioner is going to need 120 volts to run. This will require an inverter.
- Amps (A): Amps measure the rate at which electricity flows in a circuit. To calculate amps, you can divide the watts by the volts. For example, if your AC uses 1500 watts and operates at 120 volts, the current draw would be 12.5 amps (1500W ÷ 120V = 12.5A).
You’ll often hear someone say they have “400 amp hours” of batteries. If they have 12v batteries, that would mean they could have a 400 amp draw at 12 volts on their batteries for 1 hour to bring them down to completely empty. Many batteries will cut off prior to being completely empty, but you get the idea.
Formulas & Calculations
You can use the formula below to understand how volts, amps, and watts interact.
- Volts x Amps = Watts
- We have 600 amp hours of 12 volt batteries. 12 volts X 600 amps = 7,200 watt-hours of house batteries
In terms of available energy, this would be exactly the same as 300 amp hours of 24 volt batteries. Both are 7,200 watt hours.
As we dive deeper, it is easiest to think in terms of watts and watt-hours.
Depending on YOUR specific RV, volts and amps can vary from another person’s RV, but watts can be thought of as a comparable metric of power regardless of how many volts or amps are being consumed.
AC Power vs. DC Power
Alternating current, or AC for short, is the type of electricity you’ll find in your home. When you plug something into an outlet in your house, that is AC power coming from the outlet. Alternating current does just that. The flow of electricity changes direction frequently. All the power lines that you see when driving around will be AC electricity as it is more efficient to carry over long distances than direct current (DC) power.
With the exception of driers and a few other specialty electric items (welders, etc.), electric items found in a typical North American house will use 120 volt AC electricity. At a campground, you’ll usually see 50, 30, and 20 amp service (power) at the pedestal. This is because some RVs use 50 amp while others use 30 amp. You’ll see 20 amp power for extension cords or other miscellaneous appliances.
You’ll also hear AC power referred to as “shore power” in the RV community. When someone mentions shore power, they mean plugging their RV into a power pedestal at a campsite, or even “moochdocking” and plugging into an extension cord from a house outlet!
Direct current, or DC for short, is used in applications that are not connected to the power grid. Things like RVs, cars, boats, etc. all use DC power as they don’t always have access to AC. Direct current is also aptly named. It sends electricity in a constant direction.
DC voltages are typically lower (common voltages for RVs are 12v, 24v, and 48v) which means higher amperage. We’ll talk more about amps in a bit. If you get electrocuted by direct current electricity, it doesn’t “let go” like AC power will, which is all the more reason to be extremely cautious when dealing with electricity.
What Else Can Solar Power?
This is somewhat of a trick question. In every off-grid solar setup I’ve seen or built, solar doesn’t directly power anything.
Solar charges the batteries, and the batteries provide all power.
To understand what else solar can power, you need to know if there is an inverter. If you aren’t familiar with the function of an inverter, take a minute to read our article on what an RV inverter does.
If there isn’t an inverter available, then you’ll only be able to power items that run on DC power. This includes an RV fridge, lighting, water pump, fans, TV, etc.
If you do have an inverter, then you’ll be able to power just about anything you would ever want or need off-grid. This would include an air conditioner, microwave, residential refrigerator, dishwasher, electric water heater, etc. The list goes on.
As long as you have enough solar to replenish the power you draw from your batteries, you’ll be living the good life!
RV Solar System Setup Basic Components
Now that we have discussed a bit about how solar power works and what all the terms mean, let’s take a deeper dive into the components you will need to install to run the air conditioner in your RV using solar energy.
First, you need a reasonably sized battery bank to store power overnight or when a cloudy day or two comes along.
Below are the main types of batteries. I’ve also included a chart that recommends a minimum battery bank size to power your RV AC and other appliances.
Lithium Iron Phosphate Batteries
Also known as LiFePO4 batteries, these are lightweight, compact, and have a higher energy density compared to lead acid batteries as they are based on newer lithium-ion technology. They provide a consistent voltage output and maintain their performance throughout the discharge cycle. They are also maintenance-free, require no watering, and can be discharged to a lower state of charge without risking damage. Additionally, they have a higher tolerance for temperature variations and can handle high charging and discharging rates more effectively.
Lead Acid Batteries
The traditional and widely used battery technology. They are available in two main types: flooded lead acid and sealed lead acid (AGM and gel) and are relatively affordable compared to lithium batteries.
Flooded lead acid batteries require regular maintenance, including water replenishment. Sealed lead acid batteries are maintenance-free.
Lead Acid Batteries can handle deep discharges and high current demands, making them suitable for off-grid applications. They are also readily available and can be charged using standard RV charging systems. However, they are heavier, have lower energy density, and shorter lifespan compared to lithium phosphate batteries.
If you are planning to buy lead acid batteries, I’d recommend buying deep cycle batteries, which are designed to provide a steady and sustained amount of power over an extended period.
As a rule of thumb, lithium batteries can be discharged down to about 20% while lead acid batteries can be discharged down to about 50%.
With that in mind, here are minimum battery bank recommendations.
|Lithium||4,800 watt-hours||2,400 watt hours|
|Lead Acid||7,200 watt-hours||3,600 watt hours|
We are full time RVers and power a residential fridge, microwave, toaster, air conditioner, and multiple other items. We recently increased our battery bank to 7,200 watt-hours of lithium due to the heavy power draw of our air conditioner and other appliances. Keep in mind that if you have a generator and don’t mind using it, you can get away with less battery capacity and a smaller solar array. This allows you to stay within your budget as well.
Don’t let the expense of a solar system keep you from enjoying the beauty of boondocking…there are other options and a portable inverter generator (we love our Generac 3300i) can also do the job!
Solar Charge Controller
Solar charge controllers are a vital part of powering an RV off-grid. These essential devices ensure the optimal charging and protection of your batteries. Next, let’s explore their function, different types, and how they fit into the larger system.
The primary function of a solar charge controller is to regulate the flow of electricity from the solar panels to the batteries. It acts as a gatekeeper, preventing overcharging of the batteries. By maintaining a controlled charging process, solar charge controllers help extend the lifespan of the batteries and ensure efficient energy storage.
Types of Solar Charge Controllers
- PWM (Pulse Width Modulation): PWM charge controllers are the traditional and cost-effective option. They work by rapidly switching the solar panel’s output on and off, regulating the voltage supplied to the batteries. While PWM controllers are efficient for smaller solar setups, they are less effective at extracting maximum power from solar panels when compared to more advanced options.
- MPPT (Maximum Power Point Tracking): MPPT charge controllers are the advanced and more efficient choice. They utilize sophisticated algorithms to track the maximum power point of the solar panels, continuously adjusting the voltage to ensure optimal charging. MPPT controllers can significantly increase the power output of solar panels, especially in situations where the panel voltage is higher than the battery voltage.
By selecting the appropriate solar charge controller type based on your RV’s power requirements and solar panel configuration, you can maximize the energy harvest, improve battery life, and ensure a reliable off-grid power supply for your adventures.
We use a Victron MPPT charge controller and it has served us very well!
Solar panels are one of the more important parts of an RV solar system. Without them, it is difficult to generate any solar power! All jokes aside, solar panels allow you to harness the sun’s energy.
From experience, I’d recommend having between a 2:1 and 3:1 ratio of solar watts to 12v amp hours of batteries.
We have 600 amp-hours of batteries, so between 1200 and 1800 watts of solar power is enough power for most use cases.
If you want to think about your batteries in watt-hours, I’d say 200 watts of solar for every 1,000 watt-hours of batteries is a comfortable level.
We have 7,200 watt-hours of batteries. That would mean we should have 1,440 watts of solar panels. In reality, we have 1,700 watts of solar panels to provide a little buffer on cloudy days.
An inverter is a device that converts direct current (DC) power from the batteries in your RV into alternating current (AC) power to run household appliances. It allows you to power devices that require AC power while you’re not connected to the grid. If you want to power your RV ACwhen you are not connected to shore power, you will need an inverter.
An inverter charger, on the other hand, combines the functionality of an inverter and a battery charger into a single device.
It not only converts DC power to AC power but also has the ability to charge your RV’s batteries from an external power source, such as a generator or shore power. This feature is especially useful in off-grid scenarios where you may have limited access to electricity and need to recharge your batteries efficiently.
We have a Victron Multiplus II 2,400 watt inverter charger. It has been extremely reliable and provided the power that we need.
If you spend a reasonable amount of time off-grid and want to run more than just your RV AC, I wouldn’t get anything smaller than the 2,400 watt inverter that we have.
How Much Solar Do You Need To Run An RV Air Conditioner?
I may use this answer too much to for my own good… it depends!
The amount of solar power required to run an RV air conditioner depends on several important factors, including the size (BTU or british thermal units) and efficiency of the air conditioner, your daily energy consumption (i.e. the temperature your air conditioner is maintaining), and the solar conditions in your location.
Typical factors that impact your solar energy intake include direct sunlight, any potential air pollution, and the angle at which the sun is hitting your solar array (the sun is much lower in the winter).
Types of RV Air Conditioners
For the purposes of this article, we’re only looking at mechanical air conditioners. You’ll see some folks use fans that push cold air over ice. This falls much more into the category of a fan than an actual AC.
You may also hear the term “solar air conditioner” thrown around. If you search this on Amazon, you’ll find solar powered fans, which are not the mechanical air conditioners we are talking about.
If you Google “solar air-conditioner”, you’ll find a few articles that discuss using solar power to run air conditioning in residential homes, which isn’t the topic of this article.
Let’s dig into the main types of air conditioners below.
Conventional RV AC
BTU RV air conditioners are the most common air conditioners you’ll see when walking around the campground. They are designed specifically for recreational vehicles (RVs). BTU stands for British Thermal Unit, which is a unit of measurement used to quantify the cooling capacity of an air conditioner.
A typical BTU AC is mounted on the roof of the RV. It functions much like a standard home air conditioner, but it is adapted to the unique requirements of an RV environment. The air conditioner cools the interior of the RV by drawing in warm air, passing it over cold evaporator coils, and then releasing the cooled air back into the living space.
The cooling capacity of BTU RV air conditioners can vary, typically ranging from around 5,000 BTU up to 15,000 BTU or more, depending on the size of the RV and the desired cooling power. The higher the BTU rating, the more significant the cooling capacity and the quicker it can cool down the interior of the RV.
BTU RV air conditioners often come with additional features, such as adjustable vents, digital temperature controls, and various fan speeds. Some models may also include heating elements (often referred to as heat pumps), allowing them to function as heaters during colder months.
Mini Split AC
A mini-split RV air conditioner is a compact and efficient climate control system. It is a type of ductless air conditioning system that provides both cooling and, in some models, heating capabilities.
Unlike traditional RV air conditioners that are mounted on the roof, mini-split RV air conditioners consist of two main components:
- Indoor unit – usually mounted on a wall or ceiling inside the RV
- Outdoor unit – typically placed on the exterior or in a vented compartment
The two units are connected by refrigerant lines and electrical wiring, allowing for easy installation and flexibility in positioning. The indoor unit contains the evaporator coil and a fan, which cools the air and then circulates it back into the living space. The outdoor unit houses the compressor and condenser, which release heat from the RV’s interior to the outside environment.
Mini-split RV air conditioners offer several advantages over traditional roof-mounted units, such as:
- Energy efficiency: Mini-split systems are designed to be highly efficient, which can result in energy savings and reduced power consumption. This means less solar and batteries needed!
- Quiet operation: The design of mini-split units often results in quieter operation compared to conventional RV air conditioners.
- No duct work: Since mini-split systems are ductless, there is no need for complex duct work installation or modifications in the RV’s structure. However, ducted ACs have a very clean finished look
How Much Power Does An RV Air Conditioner Draw?
Looking to know how much power a BTU RV AC will draw? The formula below is a rough guide:
Power (in watts) = BTU / 8.5
We have a two 15K BTU air conditioners. When the compressors are running, each one pulls 15,000 / 8.5, which is about 1,750 watts or 15 amps when on 120V shore power.
I’m guessing you’re interested in how much of an energy savings you can get when using a mini-split AC. A mini-split AC will use around 1/3 of the power that the standard RV air conditioner uses when running. That’s about 550-600 watts!
Using Soft Starts to run an RV AC on solar
What the heck is a soft start?
Soft starts allow your air conditioner to start up in a more phased approach, eliminating the start-up peak wattage.
For example, our Dometic air conditioner has a peak wattage startup of 5-6k watts, but only uses 1750 watts once the compressor is running. The soft start eliminates the peak wattage, when our AC turns on so that it never goes over 1750 watts, which doesn’t put additional strain on our generator or inverter.
Read more on RV inverters in our Complete RV Power Guide
Note: If your generator can handle a startup wattage of 6,000 or more watts, you might be fine without soft starts.
We installed one MICRO-AIR Easy Start soft starter and plan to install another in the near future. If you’re handy, installation is straight forward. Splice a few wires, connect a couple more and you are done! You will have to cycle your AC on and off about 5 times to let the Easy Start learn.
Running Your RV AC on Shore Power Or Off A Generator
Running your RV air conditioning when you are hooked up to shore power is straight forward, right? For the most part, yes. There are a few things to look out for depending on the amperage of your shore power connection:
Running one standard AC is about all you can do other than some lights or an efficient TV. No running a coffee pot while the AC is on!
With 30 amp, you can probably run an AC and have 1,800 watts to spare. From experience, it is tricky to run both ACs on a 30 amp connection, but you can run other larger appliances like a toaster or even an electric water heater
With 50 amp, you’re living large! Run both ACs and turn the electric water heater on. Life is good and you know it.
Keep in mind that this advice / experience applies to conventional RV air conditioners. If you are using a mini-split, your energy usage will be MUCH lower and you’ll be able to run more in addition to your air conditioner.
Doing the Math
Time to get into the numbers. I’ll take you through a real life example that takes into account the efficiency of your solar system components, including solar panels, charge controller, and inverter.
Solar panel efficiency can range from 80%-85%. Considering losses due to factors like shading, wiring, and temperature, It’s advisable to factor in a buffer of around 20% to account for these losses.
Next you want to determine the solar capacity.
Divide the daily energy consumption by the efficiency-adjusted solar system output to determine the solar panel capacity needed.
- Assume you want to run your RV air conditioner for 3 hours in a day
- At 1700 watts, that is 5,100 watt-hours
- If your daily energy consumption is 5,100 watt-hours and you have a solar system with 80% efficiency, you would need solar panels capable of producing approximately 6,375 watt-hours (5,100Wh ÷ 0.8 = 6,375Wh) of energy per day.
If you had 8 good hours of sunlight per day, this would equate to about 800 watts of solar panels.That doesn’t account for any other electrical usage! In the above scenario, I think 1,200 watts of solar power would be a better estimate to make sure you have enough power to recharge your batteries.
To ensure continuous battery power supply, you’ll also need to factor in your battery capacity. Determine the size of the battery bank understanding that you won’t always have sunny days.
Consider the depth of discharge (DoD) to maintain battery health and longevity. A commonly used DoD for lead-acid batteries is 50%, while lithium batteries can handle deeper discharges down to 20%.
Using the above scenario with a 1,200 watt solar array, I think a bare minimum of 400 amp hours (4,800 watt-hours) of lithium batteries and 600 amp hours (7,200 watt-hours) of flooded batteries would be adequate. If you don’t mind the expense, a little extra battery capacity never hurt anyone!
How to Determine Your Energy Needs & If Running Your RV AC on Solar is Right For You
So now that you’ve done the math on how much solar power you’ll need to run your RV AC, it’s worth doing a final check to see if this decision is right for you.
A reliable RV solar setup that will comfortably power an AC is quite an investment. Here are the main items you should consider before diving in:
Is the financial investment worth it?
If spending the extra money on a larger solar system doesn’t matter to you, then go get your solar system and have a blast on your off-grid adventures!
If you are on the fence about how much money to spend on a solar setup, then keep in mind that you can buy a generator and a lot of gas for fraction of the price. Perhaps a combination of solar and generator is the proper solution.
How much will you boondock?
If you are boondocking a couple times a year, investing in a large solar setup probably isn’t worth the money. You’d be better off getting a smaller solar setup and supplementing with a generator to run your AC.
How hot will it be where you are boondocking?
Is your plan to avoid the warmer temperatures or face them head on when boondocking? Facing warm weather is inevitable. However, you should still weigh the pros and cons of how much you’ll actually need to run an AC while off-grid.
Whether you plan to install a small or large solar system, you are making a great step towards powering your RV with renewable energy. Good for you!
Why Would You Want A Solar Package on Your RV?
If you can simply run your air conditioner with a generator, why would you bother with the expense of a solar setup? When it comes to RV travel, embracing solar power can be a game-changer and it certainly has been in our case!
Let’s dive into the reasons why a solar power system is a must-have for your off-grid adventures.
- Renewable Energy Source: Harnessing the power of the sun allows you to tap into a clean and renewable energy source and minimize your carbon footprint. By utilizing solar panels, you can reduce your reliance on fossil fuels (gasoline, diesel, propane) and contribute to a greener planet. Solar energy is abundant, readily available, and completely free once you’ve made the initial investment in your solar system.
- Dry camping and Boondocking for FREE: With solar power, you can venture off the beaten path and experience the freedom of dry camping and boondocking without worrying about electrical hookups or campground fees. Solar panels convert sunlight into electricity, providing you with a self-sufficient power source to run essential appliances and charge your devices while enjoying remote and scenic locations.
READ MORE ABOUT OFF-GRID CAMPING IN OUR COMPLETE GUIDE TO RV BOONDOCKING
- Running an Air Conditioner without a Generator: One common challenge of off-grid RV living is maintaining a reliable power supply for larger appliances like an AC. Solar power eliminates this concern. With an appropriately sized solar system and battery bank, you can power energy-hungry appliances like ACs. Enjoy comfortable temperatures when you find yourself in an unexpected heat wave.
- Power Even During a Power Outage: Solar power provides a reliable backup option during unforeseen power outages. While others may be left in the dark at RV parks, your RV can remain operational with a well-designed solar system. Whether you’re camping in remote areas or facing disruptions in traditional electrical supply, having solar power ensures uninterrupted comfort and peace of mind.
The decision to equip your RV with solar power goes beyond being environmentally friendly. It unlocks a world of freedom, sustainability, and independence.
Fulfilling Travel Tips
Diving into the world of off-grid RVing and boodocking can be exciting, overwhelming, daunting and confusing… often all at the same time!
To help you navigate the watts, amps, and volts of it all, here are a few of our other guides to help you prepare for the adventure and freedom of dry camping and RVing to beautiful destinations:
- How much solar do you need to run an RV fridge?
- RV Boondocking For Beginners: How To Live Well in Wild Places
- 51 Best Boondocking Tips
- What Does An Inverter Do? A Complete RV Power Guide
- RV Tips 101: Education Guide For Beginners
- Ultimate RV Maintenance Checklist
- Best RV Travel App For Planning, GPS, and Camping
- Starlink Roam For Remote RV Internet
And here are some stunning places to camp for free while you bask in the bliss of your air conditioner running on solar while camping off-grid:
- Beautiful Free Camping in Telluride At Last Dollar Road
- Nomad View Dispersed Camping Near Badlands National Park
- RV Camping on The Beach At Lake Powell
- Best BLM & Free Camping in the U.S.