What Size Generator Do I Need for My RV?

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The other weekend we went camping with some friends. The state park we stayed didn’t have any hookups (no electricity, water, or sewer).

Mike and I are fine without extra amenities since we can fill our RV water tank before we leave and we have an onboard generator.

Our friends have a pull behind, and though they can fill up with water, they lack a generator. Initially, when they bought the camper, they didn’t see a need for a generator. However, since then, they have changed their minds.

Typically, we don’t run our generator a lot, but this past weekend, it was extremely hot, and we kept our generator running most of the weekend.

We needed to run the generator to keep the air conditioner running.

Are you wondering why we would go camping only to sit inside? I would be too! 

We ran the generator for our pets. Our cat and senior dogs don’t do well with hot temperatures, so we kept the AC running for them.

Unfortunately for our friends, their camper was so unbearably warm they had a hard time even sleeping. 

Not only was it hot, but it was also humid without even a hint of a breeze. Of course, by the first night at dinner, they were discussing the need for a generator.  They were both pretty frustrated since they have an AC unit, but they had no way to run it.

Having an on-board generator is an absolute must for us with our pets. But even without pets, I would have a hard time not having a generator. 

It allows us to camp just about anywhere since we aren’t restricted to only campsite with hookups.

Also, I love the convenience of being able to flip on the generator at rest stop to make lunch or turn on a movie on a rainy day.

What is a Generator Used for in an RV?

So, this is a good time to discuss the three types of energy sources in most RVs. 

First, is propane. Propane is used for the fridge, when not hooked up to electricity, water heater, stove and oven, and the furnace.

Second, the house batteries. Our RV has two batteries; some have three or more others have only one. 

These batteries run the lights, and if the RV has them slide outs, electric step, awning, and anything that can run at 12V like the furnace fan.

Third, is the generator, if your RV has one. If not, you need to plug into an outlet to use anything that runs higher than the 12V.

Which brings me to what the generator is used for in the RV:

  • Entertainment centers
  • Outlets
  • Air conditioning
  • Microwave

A house battery can only run a minimum of items, and if used in excess, the batteries can die.

When Mike and his friends were camping, they used his friend’s pull behind. It was late fall, so the evenings were pretty cold.  Before bed, they turned on the furnace.

Unfortunately, in the night, the house battery died, causing the furnace fan to shut off.

Though it is nice to have the house battery, it is limited to what it can do.

How to Determine How Big of a Generator You Need

The air conditioners are what pull the most energy, so figuring out what you need to run your AC is the first step.

The minimum wattage you require for a generator needs to be equal to the starting wattage of the AC unit. 

AC units take more power to start than it does to run them.  

Remember if you have more than one AC unit, you need to take both into account.

After figuring out the starting wattage of the AC, you can look at other appliances’ wattage needs.

Finally, don’t forget to figure in the wattage of your plug-in items like hairdryers, fans, and coffee maker.

I recommend using the Honda Calculator. This calculator allows you to pick which options you have in your RV. It takes into account things like AC size, coffee maker, and refrigerator.

What Size Generator Do You Need for a 30 Amp RV?

The maximum wattage a 30 AMP RV can handle is 3600 watts.

What Size Generator Do You Need for a 50 Amp RV?

The maximum wattage a 50 AMP RV can handle is 1200 watts.

Another useful calculator is the watts to amps calculator.  The watts to amps calculator you have three options to pick from first:

  • DC – Direct Current
  • AC – Single Phase: Has one power wire
  • AC – Three Phase: Has three power wires

Things to Consider when Choosing a Generator

Besides the wattage amount, there are other factors to consider when purchasing a generator for your RV. Below is a list of factors to think about when deciding on a generator.

  • Size and Weight – We used a portable generator for our pop-up camper. The generator was too heavy for me to help lift, so we always had to have a friend come over to help load it into the back of the truck.  We made it work, but it would have been ideal to be able to have one I could have helped move.
  • Decibel – Some generators are louder than others, they all have a sound rating. It may not seem that important, but on one of the earlier RVs we used, the noise from the generator drowned out the speaker on the TV.
  • Cost – Generators are a lot more expensive than I had originally thought, but thankfully, they can have a pretty long lifespan.
  • Fuel efficiency – If you want to spend a long weekend camped out in the woods, you need to have a generator that won’t burn through the fuel too quickly.

Final Thoughts

A generator isn’t a necessity, but it definitely makes things easier. If you are camping without any hookups, it’s great for hot or rainy days.

Also, you can run the generator while driving in a motorhome. We run ours on hot days as it helps to cool the RV down faster.

Outside of using it for the air conditioning, it is definitely a luxury.

Also, most RV parks have hookups for electricity. However, not all national or state parks do, so having a generator opens up more options on where you can comfortably stay.


How many watts does a 30-amp RV use?

A 30-amp RV can use up to 3600 Watts.

 Will a 3000-watt generator run an RV air conditioner?

Depends on your air conditioner starting wattage needs.

 Can I plug my 50-amp RV into a 30 amp outlet?

Yes, but you will not be able to run the RV at its full power capacity.

 How big of a generator do you need to run a camper air conditioner?

It depends on how much energy your air conditioner needs to get started; the amount of power to run the AC is less than what it is to start it.

 What kind of maintenance does a generator require?

Generators need to have the oil, oil filter, and air filter changed. Maintenance is based on the generators run time.

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