RVs with solar prep and campers with factory-installed solar charging systems are no longer the future. They’re here to stay, and more RVers stand to benefit from improvements in RV energy systems. But these improvements raise an important question: can you run AC with solar power in an RV?
The answer is perhaps more nuanced than you might imagine and requires a deeper understanding of common solar charging systems used in RVs. So, let’s dive in.
How Does a Solar Charging System Work?
In the simplest terms, an RV solar system requires panels to capture solar energy, a charge controller to regulate that energy, batteries to store it, wiring to transfer it, and an inverter to change it from Direct Current (DC) to Alternating Current (AC) if you wish to use it for larger appliances like your air conditioner.
Most RV solar panels are rated for 100 to 220 watts, and common lead-acid RV batteries are rated for 80 to 100 amp hours. RV inverter sizes vary, with ratings ranging from 1,000 to 5,000 watts. The effectiveness of a solar charging system for off-grid camping will depend on the number and size of the panels and the storage capacity of the batteries. However, your energy usage and, perhaps most importantly, the availability of direct sunlight will also play a major role in the usability of an RV solar charging system in a boondocking setting.
Can You Run an RV Air Conditioner With Solar Power?
With the right solar charging system, an RV air conditioner can be run “on solar power”. However, storing the amount of energy required to start and run an RV air conditioner can be a major challenge. In common RV solar charging systems, solar panels capture solar energy, and a charge controller regulates that energy as it is wired into a battery bank for energy storage.
Without a compatible RV inverter, battery energy can only be used to power 12V appliances inside your RV. An inverter and the proper wiring convert the DC power stored in your batteries to AC power for larger appliances—in this case, your air conditioner.
There are many variables to account for when determining if you can use solar to cool your RV, such as:
- Number of air conditioners on your RV
- Size and electrical ratings of those air conditioners (starting and running wattages)
- Use of an RV AC soft start
- Air conditioner usage (hours, temperature settings, fan speed, etc.)
- Size and number of solar panels (roof-mounted and/or portable)
- Battery bank capacity (number and type of RV batteries)
- Inverter rating
- Hours of direct sunlight exposure while camping
Technician Tip: Even a system designed to run an air conditioner without RV hookups may fail if your panels don’t receive enough sun exposure to recharge the battery bank.
If the sun were shining on a clear day for 12 hours, it would require about 36 420-watt solar panels to run a single 1,500-watt A/C and recharge the battery bank so the A/C can continue to run at night. Since the sun doesn’t always shine, 16 100 amp-hour lead-acid batteries per 24-hour period would also have to accompany the solar panels.
However, lead-acid batteries will wear out in a year or two if regularly discharged below 50%. If you switched to 100 amp-hour lithium iron phosphate batteries, you could feasibly rely on eight batteries because they can be 100% discharged with no negative consequences. However, those batteries are significantly more expensive.
The bottom line is that there simply will never be enough RV solar panel real estate on the roof or battery storage space in the compartments for that much equipment.
Is There an RV Solar Air Conditioner?
Many companies are now manufacturing 12-volt DC air conditioners that directly replace the traditional styles. Many are already coming as a stock option on production model RVs. These can be operated with a large LiFePo power bank that can offer up to 16,000 watt-hours of energy.
This will be run through a digital inverter/charger combo to run inductive cooktops, a DC air conditioner, electric heaters, and convection microwave ovens in what looks like any other traditional RV.
For these setups, a minimum of six 420-watt panels would readily maintain the charge on sunny days. Shore or generator power can also recharge the power bank since the same inverter/charger can utilize those energy inputs as well.
How Much Solar Does it Take to Run an RV AC?
While this is a common question, the more accurate query would be: How much energy does it take to run an RV AC? That will depend on the size of the air conditioner, but a 30-amp RV with a single air conditioning unit will likely require at least 3,500 watts of energy output to start and run the AC. A 50-amp RV with dual air conditioners will require between 6,000 and 8,000 watts, and a luxury RV with three air conditioners will require 10,000 to 12,500 watts.
Every RV air conditioner is rated for running watts and starting watts. The starting wattage is higher, and the running wattage tells you how much continuous power is required to keep the AC running. Many also recommend accounting for inefficiencies in the system by multiplying your air conditioner’s power ratings by 1.25. Here’s an example:
30 amp RV with a single 15,000 BTU air conditioner
Starting wattage = 3,500
Running wattage = 1,500
3500 x 1.25 = 4,375
1500 x 1.25 = 1,875
These calculations tell me that my solar charging system must be capable of supplying roughly 4,375 watts to start my air conditioner and a continuous supply of roughly 1,875 watts to keep it running. Of course, this assumes that no other appliances are pulling from the battery bank during the period of AC usage.
Is It Worth Converting an RV to 100% Solar?
The big question for RVs is whether solar energy can be effectively stored in the battery bank. In most cases, the answer is no. Even RVs with solar panels as a standard feature are typically not built to run an air conditioner without RV hookups.
That said, there are solar generators that can power an RV air conditioner when off-grid. These are portable generators designed to recharge with compatible solar panels. Like any portable generator, they must supply sufficient power output to safely start and run the air conditioner(s) in your RV, based on the number and size of the units.
For those committed to off-grid camping, the question often comes down to a solar generator vs a gas-powered generator. Cost-effectiveness and reliability are two key considerations. You’ll find the best portable generators that use gas at a similar price point (or often cheaper) when compared to solar generators. While solar generators can eliminate additional fuel costs, they come with a major reliability question mark. What happens if the sun doesn’t come out?
In reality, most boondockers will rely on a combination of a gas-powered generator and solar panels to extend off-grid stays. A properly chosen portable generator is the smartest choice for running an RV air conditioner during the hottest parts of the day. Solar panels are useful for maintaining battery charge while you’re away or in transit.
Are There New RVs That Run on Solar Power?
Can you run an RV 99% on solar? Sure! However, it will typically require a full system conversion. Buying a new camper with these systems installed as stock is the most cost-effective way to go. Converting an existing camper (while possible) means removing the existing equipment and replacing it with new.
At this moment, buying a new camper that is total electric/solar/lithium will cost about $10-15k more than the same camper in a traditional gas/shore power configuration. Converting a traditional RV to total electric/solar/lithium will run at least $30k plus labor. Some existing models with added solar capability include the Forest River Wolf Den 16EV and the Keystone Outback OBX.
The encouraging news is that solar technology continues to improve. There are numerous RV solar kits and systems to help you “upfit” your RV for extended off-grid camping. While a portable or onboard RV generator remains the most reliable and economical method for utilizing large RV appliances without a power hookup, retrofitting your RV with an upgraded solar charging system is more possible than ever.
If you want to learn more about designing and installing a capable solar charging system for your RV, contact our RV Performance & Installation Division.
