What size generator for 30 amp RV?

Do you need to power your RV but don’t know what size generator to buy?

We can help! In this guide, we’ll walk you through everything you need to know about generators for RVs. We’ll explain the difference between 30-amp and 50-amp services, show you how to calculate your electrical needs, and help you choose the perfect generator for your needs.

Whether you’re looking for a portable RV generator or a built-in model, you want to run your air conditioner or the entire load of your RV. We can guide you with all the important things and the generator features that you should consider before purchasing.

Read through this complete article on our website to know all this.

What is an RV generator?

An RV generator is designated with the task of providing electrical power to the various equipment and electrical appliances in your RV through the circuit breaker panel. This includes powering the converter/charger associated with the RV house batteries.

As you may be aware, a house battery is the 12 V battery that powers your RV appliances like microwave, refrigerator, and TV. It is a deep cycle battery with much thicker plates than the normal ones and is not affected by frequent charging & discharging cycles and vibrations. They can provide a steady current over large durations. You may have more than one such battery to power your appliances if you have a higher electrical load or desire power over a longer duration.

You have two options for your RV – Fixed mounted built-in RV generators or portable generators. Their relative advantages and disadvantages are discussed below.

Portable RV Generators

The portable RV generator can be either a conventional generator or an inverter generator, depending on the usage and how much power you need. A generator with the inverter technology has the benefits of higher fuel efficiency with lower fuel consumption, lower noise level, extended engine life, provide clean power suitable for use with sensitive electronics, and easy parallel capability.

A portable generator is not directly built-in to your RV vehicle and is usually available in the range from 1,000W to 10,000W, usually on the lower end of the spectrum. They cannot use fuel from the RV tanks directly; you need to refuel them separately. You should not use them if the vehicle is in motion. Gasoline or LP is the preferred fuel type for these generators.

On the plus side, you can use a portable generator for other applications like tailgating, camping, at any worksite, or at your home for selected power needs.

Built-In Generators

Built-In RV generators are pre-installed inside your vehicle and are many times designed to use the fuel from the RV fuel tank. They can run on either gas, LP, or diesel and provide higher power output in the range of 2.5 kW to 12.5 kW. RV generators are equipped with a push button and auto electric start feature.

The use of RV tank fuel allows them a longer running time and the ability to operate even when your vehicle is in motion. For bigger RVs belonging to class A and class C, built-in generators are the only option.

How many watts does a 30 amp RV use?

As the name suggests, a 30 amp RV is designed for 30A single phase AC current power usage at 120V.

30-amp receptacle

Most generators feeding power to small and mid-sized RVs and trailers use NEMA TT-30R outlets, where TT denotes a “Travel Trailer.” These outlets are also designated as RV 30; any generator equipped with these outlets is designated as “RV ready.” Further, these outlets are rated for supplying 30 amp current at 120 V, with three-pronged hot, neutral, and ground pins.

Hence, theoretically, they are designed to cater to the power usage of about 3.6 kW. This is the maximum power a 30 amp RV can use.

What is a 30-amp service?

A 30Amp service is an electrical system consisting of plugs, receptacles, circuit breakers, etc designed to allow input power equivalent to a single phase 30A current at 120V only.

What is the difference between a 30A & a 50A service?

Hopefully, you have clearly understood the concepts related to a 30A RV, service, and receptacles. Along similar lines, a 50A service comprises a system with all associated plugs, receptacles, and protective devices to receive 50A power at 240V. This equates to a power of 12 kW against the 3.6 kW power in the 30 amp RVs.

NEMA 14 receptacles and plugs are equipped with four wire grounding devices, two of which are hot connections. Bigger size generators have 14-50 outlets to feed power to 50A RVs. These connectors are available in many RV parks to shore power for these large RVs and also find use in electric vehicle charging applications.

Can you plug a 30-amp RV into a 50-amp power source?

Many of the RV parks provide 50 amp service. Hence, it is entirely possible to connect your 30A RV to a 50A plug at an RV campground with a 30 amp to 50 amp adapter. The adapter has a 50A male end and a 30A female end. The adapter’s male end should be connected to the power pedestal and the people end to your Rv cord.

Can you run a 50 amp RV on a 30 amp generator or Power pedestal?

Like the previous case, it is possible to do so with the proper adapter, as many campgrounds only have a 30 amp power source. The adapter is similar to the previous one, except the female end is rated for 50 A and gets connected to your RV cord, whereas the male end, rated for 30A, is connected to the power pedestal at the campground.

It is important that you will not receive enough power to operate all your appliances at the same time and will do better to switch off your power-hungry appliances.

Will a 3500-watt generator run a 30 amp camper?

As already explained above, a 30 amp RV can use 3.6 kW power on the higher side. So, a 3.5 kW can easily run near the full capacity. On the minimum side, you can go for a 2.5 to 2.8 kW generator and a 4 KW generator to cater to slightly higher startup watts on the higher side.

What size generator do I need to run everything in my RV?

The different types of RV that you encounter in the market and their tentative sizes of generators are:

  1. Class B RV van with a single air conditioning unit (AC) – 2 to 3.6 kW
  2. Class C RV with a single AC unit – 2.8 to 4 kW.
  3. Class A RV with two ACs of 15000 BTU/hr each – 5.5 to 8 kW
  4. Class A RV with three AC units of 15000 BTU/hr each – 10 to 12.5 kW
  5. Five-wheel RV with two ACs – 6 to 8 KW.

These are typical sizes based on common usage patterns that could change based on your specific equipment selection.

How do I calculate my electrical needs?

The first step is to list down all your electrical appliances with their actual power rating. The below list, provided for your guidance, contains common appliances used on RVs and the estimated range of running power consumption. The actual consumption may vary based on actual ratings, capacities (for example, the capacity of the fridge in liters), makes, condition, and age of the appliances, and usage.

  1. RV air conditioner units – 1250 W (R) and 3000W (S). This is discussed below in a separate section.
  2. Dishwasher – 700 W (R) and 1400 W (S).
  3. Microwave Oven – 750 W (R) and 750 W (S)
  4. Refrigerator (Small) – 200 W (R) and 500 W (S)
  5. Coffee Maker – 600 W (R) and 600 W (S)
  6. Electric Kettle – 1200 W (R) and 1200 W (S)
  7. Toaster – 800 W (R) and 800 W (S).
  8. TV – 200 W (R) and 200 W (S).
  9. Laptop & Printer – 200 W (R) and 200 W (S).
  10. Hair Dryer – 1200 W (R) and 1500 W (S).
  11. Any other appliances

This list is just for guidance. You need to prepare the list of equipment you have on your RV and populate it with your appliances’ actual running and starting wattages. You need also to figure out the usage pattern, including the list of appliances that you will run continuously.

Choosing generator wattage

As already explained above, as a thumb rule, Class B and C RVs require between 2 to 4 kW of power, which nearly matches the power a 30 A service can handle. So these numbers represent the boundaries between which you have to work.

If your running watts came higher in the calculations, then you cannot run all your appliances simultaneously and need to stagger the usage. For example, some of your high-running power equipment for cooking (coffee maker, toaster, kettle, microwave) or dishwasher may be required for shorter durations in a day and not together. A more important consideration is that you should always be able to power your base load (continuous running equipment).

The standard procedure for sizing a generator is

  1. Add the running watts of all the equipment. As discussed above, you can use the modified running watts if you have prepared a plan to run the equipment in a staggered pattern. You can call it X.
  2. Select the equipment with the highest starting watts (Y) from all your appliances.
  3. Add X and Y. The running watts rating of our selected generator must exceed X, and its starting watts or surge watts rating must exceed X + Y in ideal situations.
  4. As you have constraints on the power your RV can take, you may need to start the largest equipment first, keep track of the power you are drawing, and shut down the equipment you are not using before switching others.

As stated above, you can go up to a 4KW running watt generator to have additional motor starting power.

How Big Should My Generator Be to Power My AC Unit?

Typically, a 15000 BTU/hr unit will consume about 15000/10 = 1500 W power assuming the SEER rating of the unit to be 10, on the conservative side, and assuming an older unit.

This is because AC Wattage = AC Capacity (in BTU) / EER Rating

All modern AC units have SEER ratings upwards of 12. In that case, the power required is 15000/12 = 1250 running watts. So you need 1250 to 2400 watts to run this size AC, depending on the SEER of your unit, age, and condition of the unit and the generator, and to cater to its starting currents.

Parallel Generator Operation

You can use two parallel inverter generators of about 2 kW instead of a single 4 kW generator. An inverter generator parallel kit or paralleling cables provides easy means to parallel two generators. Two generators are more portable, adding to the flexibility that one can be switched off during low power demand. This helpful video provides guidance on setting up the parallel operation for different brands of generators.

What should I look for in a 30 amp generator?

Some of the important features to look for in a generator are they should be

  1. Fuel efficient with smart economy mode.
  2. Must have Carbon monoxide protection.
  3. Dual Fuel Generators (LP or gas-powered generator) gives you more options with fuel availability.

Other Factors to Consider

In addition to the power ratings like maximum wattage, running watts, and starting watts, there are a few more things to consider before you go ahead with your purchase of the RV generator.

Noise level

Unfortunately, no standard exists governing the noise levels from the RV generators. However, the National Park Service (NPS) specifies a requirement of 60 dB (A) at 50 feet distance. 60 dB (A) is the sound from a normal human conversation. Hence, a rating of 70 dB (A) at a distance of 10 m should be comfortable for you as well as any other RV owners in your neighborhood.

Important considerations for the noise level rating are

  • They vary with the load on the generator and should be measured at their maximum power rating.
  • They vary with the distance and the angle of the measurement.

If you are going in for inverter generators, they inherently produce lower noise levels, as they run at lower speeds to match the loads.

Generator fuel

As stated above, you can choose between LP, gasoline, and diesel fuel. Each option has its benefits and shortcomings.

LP and gas generators have a lower capital cost in addition to their smaller size and lower weights. These lighter generators with smaller footprints allow you to optimize the floor plans on your RVs. You get a lesser smell from exhaust fumes.

The diesel versions have a longer lifespan along with lower fuel consumption and cost. The combination of less fuel consumption with lower prices provides you with a better fuel economy. In addition, you can run your generator from your vehicle’s fuel tank for additional flexibility.

Weight & Portability

Portability, hence indirectly, the weight of the generator is another important consideration as you may need to take the generator in and out of your RV repetitively. Higher weight will also result in higher fuel consumption of your RV. If you require a bigger generator size, consider going in for two smaller generators to increase the portability.


So, now you know the answer to the question – “What size generator for a 30 amp RV?” A portable RV generator that puts out 3,500 watts or more should do the trick. Remember to always leave some spare wattage in case you need it for an extra appliance or two. And finally, if you are still unsure about what size generator is best for your needs, feel free to drop a comment below, and I will try my best to help you out.

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