How to Properly Size An RV Generator? (for Boondocking)

How to Properly Size An RV Generator? (For Boondocking)

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Size is a crucial factor when choosing a generator for RV boondocking.

A small generator will not be able to power all the appliances you need to run. A larger unit will be a waste in terms of power and fuel consumption.

So, if you want to have a good time out while dry camping, finding the right size RV generator should be your top priority.

But, what size generator will be the best for your RV?

To determine the appropriate size generator, you need to find the size of your RV and the number of appliances you’ll be running. Generally, most weekend dry campers will be fine with a 3000 to a 4000-watt unit. Such a generator will power a rooftop AC, run a few other small appliances and charge the house batteries. 

However, every RVer is different in terms of power needs, and as such, you need to calculate your total power needs to size your RV generator appropriately.

In this post, I’ll help you determine your total power needs so that you can get the right size portable generator for your upcoming trip.

But, before that, let’s start by looking at some basics of electricity which will help you make the right decision.

Read More: Find the reviews of the best portable generators for boondocking.

Few Words on Wattage

One way to find out the right size generator for your RV is to add up the wattages of all the appliances you plan to power simultaneously.

This number is a rough approximation of how many watts your generator needs to produce.

However, this number is far from accurate.

Because some appliances like air conditioners, blenders will need substantially more power, the instance they are cycling on (aka starting watts).

And without considering the starting watts, you’ll get an inaccurate estimate of the total wattage your generator needs to produce, resulting in a wrong size generator.

Here is an excellent video that talks about the differences between watts, volts, and amps.

Understanding Generator’s Starting and Running Watts

Adding up the wattages of all the RV appliances you plan to run will give you an inaccurate figure of your total power needs.

You need to factor in the starting and running watts of the appliances to get an accurate number.

But, what is the starting and running wattage?

In simple terms, the starting/peak wattage is the initial boost of electricity you need to start or wake up an appliance. While running/rated wattage is the continuous power you need to keep the device functioning properly.

Generally, the power required is substantially more to start an appliance than to keep it running.

The table below shows the starting and running watts of a few RV appliances. The numbers are an approximate estimate and will vary depending on the type, model, and brand of your specific appliance.

ApplianceStarting WattsRunning Watts
13500 BTU RV Air Conditioner28001800
15000 BTU RV Air Conditioner33002000
Microwave Oven10001000
Blender850400
RV Refrigerator600180
Laptop200200
TV190190
iPhone55
Source: HONDA

Note: Not all appliances need different starting and running watts. Only motorized or compressor-based appliances like air conditioners, blenders, etc, do.

With the basics out of the way, it’s time to proceed towards calculating your RV generator size by first finding out the type of RV electrical service it uses.

30 Amp Or 50 Amp RV: Which One do You Have?

Before adding the wattage of each appliance to find out your total power needs, you need to know if your RV uses a 30 or 50 amp service.

This will help you determine the maximum amount of power your RV can use at any given time.

To begin with, RVs that use 30 amp service is usually small and come with fewer appliances. 30 amp RV’s like travel trailers and other smaller campers are usually equipped with a single rooftop AC and a few other smaller appliances.

On the other hand, a 50 amp RV is big, comes with almost all the appliances and amenities of most modern homes. A 50 amp RV like a fifth wheel is equipped with multiple AC units, a washer/dryer, and many other appliances.

Read More: Do fifth wheels have generators?

But, how do I know if my RV is 30 amp or 50 amp?

The easiest way to find out if you have a 30 amp or 50 amp RV is to look at your RV’s shore power receptacle or plug (image above). 

A 3-pin plug/receptacle means 30 amp, and a 4-pin means 50 amp RV.

A 30 amp plug has a single 120-volt hot pin, a neutral, and a ground pin. On the other hand, a 50 amp plug has two 120 volt hot pins, a neutral, and a ground pin.

A 30 amp RV can use up to a maximum of 3600 watts and 12000 watts on a 50 amp RV in terms of power. So a 50 amp RV can use 3x more power compared to a 30 amp RV.

To Know: There is a formula to find wattage (aka Watts Law). 
Watts law states that: Power (watts) = Voltage (volts) x Current (amps).
120 (volts) x 30 (amps) = 3600 (watts).

But, what does this have to do with my generator size?

Getting a generator without knowing how much power your RV can handle is a bad idea. For example, a generator that can produce more than 3600 watts will be a waste for 30 amp RVs.

Moreover, you need to know if your RV is a 30 amp or a 50 amp to find the right size generator to power your whole RV.

By now, you know the type of electrical service your RV uses. Now, let’s move on to finding the right RV generator size by calculating your power needs.

If You’re Interested: I have 2 detailed posts on finding the right size generator for your 30 amp and 50 amp RV.

How Much Generator Power do I Need for my RV?

To find out the exact generator size for your RV, you need to find the total power you’ll need to run your appliances.

To find the total power, you need to list down the wattages of all the appliances you plan to use daily.

Especially the high draw appliances you want to run simultaneously.

Here is a list of appliances with their starting and running watts.

ApplianceStarting WattsRunning Watts
13500 BTU Air Conditioner28001800
15000 BTU Air Conditioner33002000
Hair Dryer (1600 watts)19001800
Electric Grill (tabletop)16501650
Microwave Oven (650 watts)10001000
Blender850400
5200 BTU Space Heater750750
Coffee Maker600600
RV Refrigerator600180
Laptop200200
TV190190

Here are the steps to calculating your total power.

Step #1: Make a List of the Appliances You Want to Run

To accurately size a generator for your RV, first, make a list of all the appliances you want to power using your generator.

List down both the starting and running wattages of the specific appliances of your RV. 

You’ll find the wattage ratings of your specific appliances on the label of the appliance or use the user manual to find it.

Make sure the list is in the ascending order of the starting watts of the appliances (like the way I’ve arranged below).

Here a list of the appliance for my 30 amp travel trailer:

  1. 13500 BTU Rooftop Air Conditioner
  2. Microwave
  3. Coffee Maker
  4. RV Refrigerator (2 way)
  5. Laptop
  6. TV

Note: I’ll use the wattage ratings from the table above to keep it simple to understand.

Step #2: Add Up the Wattages of the Appliances

In my list above, I’ve six appliances that will be powered using my generator regularly.

You may have more or less depending on the type of RV, number of people.

However, I am never going to power all the appliances simultaneously, and nor should you.

For example, I’ll never run the microwave, coffee maker, laptop, and TV all at once.

On a typical warm morning, I’ll fire up my generator to power my air conditioner. Then, switch my refrigerator from propane to electricity.

Next, I brew myself a cup of coffee while making breakfast on my propane stove. As I enjoy my breakfast, I may turn on my TV to watch some news and get my coffee down as well.

After breakfast, I usually turn on my laptop to start working as I am a freelance digital marketer.

Pro Tip: Finish working with one appliance before starting another. For example, I’ll only use my microwave before brewing my coffee or wait till my coffee is ready. This simple adjustment can help me run more appliances on a small generator.

For me, I need a generator that is a minimum of 2800 watts, as my AC needs that power to start. Once the AC is running, it uses 1800 watts to keep running, giving me 1000 watts of extra electricity to power other appliances.

The remaining 1000 watts is sufficient for running the other appliances.

Generally, you just need to get a generator that can start your biggest appliance.

And in most cases, it will be your air conditioner.

However, if your RV comes with multiple rooftop AC units and you need to use them together then make sure you size your generator big enough.

If You’re Interested: I have a detailed post on how to find the appropriate size generator for your RV air conditioners.

Let’s say, your rig comes with two AC units (15000 and 13000 BTU).

From the wattage chart above, a 15K BTU air conditioner needs 3300 watts to start and 2000 to run. A 3300 watts generator will run your 15K unit but will not be able to start and run the 13.5K unit.

Your generator needs to produce about 5100 watts of power to start and run both your ACs. Plus you’ll have extra electricity at hand to run a few smaller appliances.

How did I get this number?

I just added the starting wattage of the highest draw appliance with the running wattage of the second-highest draw appliance. This way I get a wattage rating that’s not very big but powerful enough to keep me comfortable.

Step #3: Get a Slightly Bigger Generator

For my small camper with one air conditioner, a 2800 watts generator will do it for me.

However, you need to get a generator that produces a bit more power than what you need.

A good rule of thumb is to add 20% to the total wattage you need.

This will ensure you have extra power if you need to run a big appliance that you don’t need often. Additionally, the extra power will prevent your generator from running at full load, reduce noise, fuel consumption and extend the generator’s life.

Therefore, calculate the total wattage you need and add 20% to find the right size generator for your RV.

In my situation above, the Champion 3400 Watt Dual Fuel Inverter Generator will be an excellent option as it is RV-ready and has sufficient power for all my needs.

Other Factors to Consider

You now know how to calculate the total wattage needed to find the right size generator for your RV for boondocking.

But, there are other critical factors you need to consider when choosing an RV generator.

Let’s briefly take a look at each.

Get an Inverter Generator

When it comes to getting a camping generator, I highly recommend an inverter generator.

Inverter generators have more advantages over conventional generators.

They are fuel-efficient, quiet, produce clean power, and lower emissions. Most importantly, the engine varies speed depending on the load, helping extend the generator’s life.

However, inverter generators are more expensive, but they’re well worth the investment.

Note: You won’t find inverter-type generators after a certain output wattage. You can either get two parallel compatible inverter generators or use a surge protector to keep your appliances safe.

Fuel Efficiency is Important

You’ll miss out on a lot of things if you have to hit the gas station every other day because your generator is a gas guzzler.

Sure, you could stock up the bed of your truck with a lot of gas cans. But, this will create other problems and, not to mention, pose safety issues.

You’re left with one option, which is to get the most fuel-efficient generator you can find.

Though the fuel consumption of a generator can fluctuate depending on factors like load, run time, and type of fuel. But look for a generator with a higher run time on a single tank.

Camping generators usually run on either gasoline or propane. And the fuel type you should go with entirely depends on your personal preference.

However, I would suggest you get a propane generator if you’re a seasoned camper. This will save you a lot on maintenance and keep you away from the time-consuming process of winterizing your generator.

On the other hand, frequent campers have the freedom to choose any fuel type. A dual fuel generator that can run on either gas and propane or both will give you additional flexibility when deciding the fuel type.

Get an RV Friendly Generator

RV-friendly and RV-ready are two typical terms used to separate portable camping generators from others.

An RV-ready generator comes with a dedicated RV receptacle (30 or 50 amp) along with the other types of receptacles. Having an RV-ready generator allows you to connect your camper directly into the generator without any adapter or converter.

Now you don’t have to worry about losing or forgetting the adapter at home and reaching the campsite to not being able to power your RV.

Is Your Generator Quiet Enough?

Unless you have found a top-secret location to boondock, you’ll find yourself camping next to other RVers.

That means your generator has to be quiet. You don’t want to go boondocking with a generator that sounds like a jackhammer.

Generally, portable generators for camping are pretty quiet compared to ordinary generators. They fall within the acceptable noise boundaries of most National Forests and other free camping sites.

In the dry camping world, a generator that produces about 50-60 decibels is considered quiet.

Though many factors contribute to how loud your generator runs, the aim is to get the quietest unit.

Note: There are times when you need to sleep with a running generator as it is hot and you need the air conditioner. A noisy generator can make falling asleep difficult for both you and your neighbor’s.

Generator Weight

A heavy generator can be tough to load and unload on a campsite. And if you’re a solo camper, moving it alone will increase the risk of back injuries.

Yes, you can mount your portable generator on your RV bumper or keep it in a dedicated generator compartment in your RV.

But, if you don’t like the idea of mounting it or don’t have a large enough compartment, you need a lightweight generator.

There is no way to tell you what generator weight you should go for. Because everyone is different when it comes to how much weight they are capable of carrying comfortably.

I would suggest you get one that weighs the lowest, but with the output wattage, you desire. 

Generally, the weight of a generator is directly proportional to the wattage it produces. That is, a 5000-watt generator will weigh more than a 2000 watt unit.

So, you need to pay close attention when sizing your generator.

However, if your power requirements are high and need a larger unit, look for one with a handle and large wheels. You can also get two small parallel compatible generators instead of a bulky one.

To Know: Gas-powered portable generators with fuel in the tank will weigh more. However, with propane run generators, there is no weight addition from the fuel.

Price

You have found the right size generator for boondocking that fits in every aspect of dry camping.

All you’re left with is to pay, and the wild is waiting for you.

However, when it comes to price, the higher it is, the better it will serve you.

To me, the price of a product is a direct indicator of its quality.

You’ll find many generators as low as $200 to upwards of a few thousand dollars. 

Though, seasoned campers will be fine with an inexpensive unit as they will need it less frequently. But, if you’re serious about camping and hit the wild often, a reliable generator is what you need. 

My suggestion would be to get the most expensive unit you can afford.

You don’t want to go on a camping trip only to get bugged by your generator and miss all the fun.

Alternative Ways to Power your RV while Boondocking

To me, RV boondocking is all about being in nature, listening to the chirping of birds, and enjoying the silence.

But, the constant humming sound of a generator can become an obstacle.

There are alternative ways to power your RV while dry camping that removes the issues common with generators.

Among them, the most popular boondockers are using solar power. You need to invest in a suitable size solar system and a set of batteries.

Your solar setup will provide DC power to run all the smaller appliances like light, vent fans, and charge devices. If you add an inverter, you’ll be able to enjoy the benefits of AC power too.

Powering your RV with solar has a lot of benefits but also comes with a few limitations. 

Wind generators are gaining popularity amongst RVers who like to camp in one spot for extended periods. Like solar, the energy from the wind generator will charge the house batteries so you can use it as you need.

But, wind generators also come with their limitations.

In the end, if you need an on-demand source of power when camping and want to power large appliances like air conditioners, a portable generator is your best bet.

Frequently Asked Questions

If you’re new to the whole generator sizing thing, you may have a few questions that may hinder your decision. 

In this section, I’ll try to answer a few questions that come up time and time again when sizing a generator for camping.

How big of a generator do I need to power my whole RV?

To size a generator to power your whole RV, you first need to know the type of electrical service your RV uses.

Generally, RVs these days come with either a 30 amp or a 50 amp power option. This is how much electricity an RV can handle at a time.

A 30 amp RV can handle about 3600 watts of power, whereas a 50 amp can handle 12000 watts.

So getting a generator that produces more than these numbers will be a waste.

What can you run on a 3500-watt generator?

A 3500 watt is a perfect size generator for RVs that sits in a sweet spot in terms of power, portability, fuel economy, and price. 

With a 3500 watt generator, you’re not losing the inverter functionality, and with parallel compatibility, you can hook up two units if you need more power.

It’s a perfect size generator for a 30 amp rig to power many appliances like AC, fridge, microwave, coffee maker, etc.

What can a 7500 watt generator run?

A 7500-watt generator is a large unit that can power a 50 amp rig comfortably.

You can run multiple air conditioner units simultaneously and still have sufficient power left to run your microwave, washer and dryer, TV, and more.

Conclusion

Generators are essential for RVers who like to camp off the grid, and finding the right size generator is above all.

You want something that produces enough power to keep you comfortable while also considering other camping parameters.

Calculate your power needs accurately and go camping worry-free.