Boondocking is arguably the purest way to use your RV. It means that you can escape from the city and into the deepest part of nature. You are not connected to anything, and your RV becomes the supplier of all your comfort needs.
The amps that an RV air conditioner uses will depend very much on the type of RV and the size of the conditioner installed. If you have a 13,500 BTU air conditioner, a regular rooftop unit will consume between 11 – 15 amps, depending on its design.
Working out the electricity usage of an RV is a complex task. The calculation must consider what electrical consumers will be running at the same time and consider the “impulse” energy requirements of items like refrigerators and air conditioners.
The Number Of Amps An RV AC Uses Depends On The Size
Knowing the electrical draw (amperage) of each appliance in your RV helps you to size the RVs electrical system correctly, so you can adequately match load against the available supply.
The measures of electrical systems are.
- The electrical current moves from the negative to the positive terminal in a circuit through the electrical consumer. Voltage measures how strong the available electrical current is.
- Amperage is the speed at which an electrical current (measured in the number of electrons) which pass a certain point. Another way of understanding amperage is that it is the maximum amount of electrical current that a system can safely handle. Therefore breakers (trip switches) are measured in amps, and if the amperage exceeds the rated value of the breaker, it trips and “switches the system off.”
To calculate the amperage draw, divide the wattage (power) rating by the voltage (current strength) from the power source.
- Wattage is the “power” of the system. It is calculated by multiplying the voltage and the amps to find the power (watts).
When looking at an AC unit for your RV, all three measures are essential.
The Voltage Requirements Of An RV AC Are Critical To Its Safe Operation
Depending on the capacity of the air-conditioning unit, it will require either a 120 Volt or a 240-volt source. Having too high a voltage will cause the compressor to burn out, and if it is too low, the AC won’t switch on.
Voltage is calculated by watts/amps. The wattage required for various sized RV ACs is listed in the following table. Assuming the RV AC requires 16 amps, you will need a 120-volt system for air conditioners with a BTY rating of 10,000 or less.
The typical wattage requirement of an RV AC is dependent on the BTU rating of the AC and is shown in the following table.
|Recreational Vehicle AC||Watts Required for start-up||Average wattage once running|
|7000 BTU RV air conditioner||1700||600|
|10,000 BTU RV air conditioner||2000||700|
|13,500 BTU RV air conditioner||2750||1250|
|15,000 BTU RV air conditioner||3500||1500|
If you opt for a higher strength unit, you will need a transformer to convert the current to 240 volts.
Most RVs use AC units with a capacity of 13,500 BTU or less. At these levels, a 120 Volt system is marginal but is capable of producing the strength of circuit required by the air conditioner if there are no other loads on the system.
It Is Important To Understand The Watts Available To Run The Unit
Any device that draws the energy from the system is called a load. The wattage (load) requirement of the RV AC unit is the total power that the unit will draw from the system; this is particularly true if you are running the RV off a solar electrical system or a gas generator. If the wattage requirement is too high, the unit will not function, or if it does, it will not run at total capacity.
The Amperage Is The Load Incurred By The Electrical Consumers.
Amperage is an accumulative measurement in a series circuit and tells you how much current you can draw from all the circuit consumers at one time.
Amperage is the load placed on the circuit by the electrical consumers. If you exceed the system’s amperage, the circuit breaker will “pop,” and the electrical circuit will be disabled.
So What Does This Mean For My RV AC?
The following discussion is based on a correctly sized voltage electrical system.
Typically, RV AC’s need 12-16 Amps to operate at total capacity. Be careful because some units require more than this.
In addition, Air conditioners need a pulse of power for the compressor to start working. The length of the pulse is measured in seconds. Still, if there is an insufficiently sized pulse available, the air conditioner’s compressor will not start, and at best, only the fan will run, which recirculates the hot air in the RV.
The amperage requirement will increase by 200% for this pulse to work while the wattage consumption triples.
The circuit breakers must be sized to handle the regular draw and the “pulse” draw every time the thermostat switches it on.
How Do You Power An RV AC System?
If you connect your RV up to the RV park’s electrical system, you will have no issue, and the system will run seamlessly.
We assume that your RV electrical system has
- a suitably sized gauge (diameter) of the electrical cabling to handle the wattage of the air conditioner. The higher the wattage and amperage the unit draws, the bigger the gauge wiring is required for the RVs wiring system.
- The RV system has sufficiently sized circuit breakers to handle the amperage of the air conditioner.
If you are going boondocking and you won’t have access to “shore” power, you will need to make sure that your RV can produce the required power levels.
The only viable way to run an RV air conditioner without “shore” power is to use a large enough gas generator or possibly if you have a sufficiently sized solar system.
To determine the size of a solar power system or gas generator, you need first to work out the average electrical consumption of the power consumers.
|Consumer||Power Requirement Watts||Number of Hours Used per Day||Daily Power Consumption||The amperage of Each Consumer||Surge Amps|
|13,500 BTU Air conditioner||3500||8||28000||16||16|
|Cell Phone Chargers||54||2||108||2||0|
Based on these figures, if every power consumer is switched on simultaneously, the power generation equipment will have to produce 8KW/’s, and 43 amps will flow through the circuit.
This table shows that the air conditioner requires a power supply out of all proportion to the other electrical consumers.
Unless you can install an 8KW system, there are ways to mitigate the power needed.
Firstly you can make sure that only the consumers which the system can cope with are switched on at any one time.
In the above example, the unit using the most draw will be the air conditioner; this is dependent on the weather and will fluctuate accordingly.
The four highest power consumers are:
|Consumer||Power Requirement Watts||The amperage of Each Consumer||Surge Amps|
|13,500 BTU Air conditioner||3500||16||16|
Remove these appliances from the system and will reduce the power requirement to
- Watts – 1,234
- Amps – 69
- Surge Amps -15
Running the RVs electrical system at lower levels would be possible by staggering the use.
The Power Sources
Now we understand the draw on the system, let’s look at the possible ways to generate sufficient energy.
Based on the above table, we will make the following assumptions.
- The maximum hourly watts to be produced are 5kw
- The average amperage will be 85 amps.
A Gas Generator Must Be Specified As Follows
A suitable gas generator produces 5.1kw of power. A suitable unit available at Amazon produces 5.5 kW and has one 30amp circuit and four 20-amp circuits.
This unit will be able to meet the power requirements described above.
Solar Power Generation Is A Renewable Solution
Solar is the greenest option and provides ready access to the energy supplied by the sun.
The downside of a solar system installed in your RV is that if the weather is overcast or at night-time, the system produces no power.
In addition, it only produces maximum power during peak sun hours every day. Peak Sun hours is the time of day when 1 kW of energy is produced by one per square meter (roughly 10.5 feet) in one hour.
To get the maximum benefit from a solar generating system, you also need to find a way to store excess electricity; this means that suitable batteries must be sourced and fitted into the RV.
Suitable battery technologies range from lead-acid units (the cheapest) to Lithium-ion units (the most expensive).
Solar batteries are rated in kilowatt-hours. A 5.1 kw/h battery can produce 5.1 kilowatts for one hour. Using the above example, this means that it can have 1.234 kilowatts watts (the power required without the high consuming items) for just over 4 hours (5,100/1,234 = 4,13 hours).
It is unlikely that all the other consumers will run simultaneously, and if there is enough discipline, one battery should last the night.
The calculation changes if an air conditioner is included in the scenario.
A 13,500 BTU air conditioning unit, will require 3.5 watts of power per hour. During a sunny day, this means that you will need solar panels capable of producing at least 3.5 kW of power. Assuming that 350-watt panels are installed, then you will need10 panels. The way to achieve this is to use portable fold-out units.
Running the air conditioner at night is not economically or logistically feasible as you will need at least ten 5.1 kw/h batteries to run the air conditioner for 14 hours through the night.
If the sun is not available the next day, the system’s batteries will be depleted, and there will be no available electrical power until the sun shows its face.
A Combination Of Power Supplies Is The Most Sensible Solution
Both gas generators and solar systems have advantages and disadvantages; however, when both technologies jointly become the solution, it makes more sense.
In this instance, if you intend to boondock away from fully provisioned RV sites and want access to most of the home away from home comforts your RV offers, you need to design an electrical system that incorporates both solutions.
Firstly, you will need to acquire a suitably sized gas-powered generator that can provide power for the following;
- The air conditioner operates as a standalone circuit.
- Sufficient power to charge the RV battery.
- Available watts to provide sufficient power to operate the balance of the electrical equipment in the RV.
Secondly, you should install a correctly sized solar power system that includes the following components.
- Solar Panels
- A Battery Bank
- A 12-volt output. Most RVs need to draw a combination of Direct Current (DC) and Alternating Current (AC). Unlike home-based solar systems, which exclusively convert the current to AC, an RV system must generate both types of electrical power.
- Solar panels produce Direct Current (DC). To convert the DC to Alternating Current (AC) for systems, such as microwaves, air conditioners, and TV, you will need to install a sufficiently sized inverter.
With the system fully operational, you will be able to run the air conditioner off the generator, simultaneously running the rest of the consumers from the solar power system.
If the sun is hidden, the generator will provide sufficient power to ensure the batteries continue to be charged.
Having sufficient amperage to run an RV AC system takes some planning to optimize the amount you have to invest.
Other than connecting the RV park’s power sources and ensuring your RV electrical system has a sufficient capacity to cater to all the electrical consumers’ amperage, you will need to make certain compromises to ensure that power is always available.
Good luck, and happy camping!
Check out our article on: How Much Does It Cost To Replace An RV Air Conditioner