Can You Run RV Generator While Driving (Portable or In-Built)

Can You Run RV Generator While Driving (Portable or In-Built)

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Generator is one of the important equipment you have in your motorhome. You need generator while boondocking or dry camping and sometimes also while driving down the road.

Many newbie RVers have this question, “can I use a generator while driving RV“.

A generator comes handy when you don’t have direct electric connection to supply the 110 v appliances in your RV.

Can you run generator while driving RV

You just bought your new class A motorhome and you are looking for an answer, to a perfectly valid and natural question.

In-built RV generator can be operated while driving an RV but it is not recommended to use a portable generator while driving. An on-board generator is an integral part of your RV and therefore, it is firmly fixed. It is also powered using motorhome’s fuel.

Thousands of people who buy their first motorhome, have this question and an answer to this question can be little hard to find.

Unless, you ask someone who has been doing this for years. I haven’t found any legal answer to this but as far as i think and the people that i have talked to, one can use a generator in rv while driving.

Not all motorhomes or rv’s come equipped with a built-in generator and thus, some people buy a separate external or a portable generator to power the 120 V AC appliances.

So, this answer does not fully apply to the people who use external generators in their RV.

We will see those points below. For now, we have a point to make, and that is “one can use the RV generator as long as you are within limits and take proper safety precautions”.

Portable generator while driving RV

As you know, not all motorhomes will have built in generator. In this case, portable is the best option.

Technically a portable generator can be used while driving an RV but has potential safety concerns and therefore they should be completely avoided while driving. Even at the campsite, make sure you place them outside, far from the RV using an extension cord and position exhaust pipe away from you.

Here are the safety concerns because of which you cannot run a portable generator in a moving RV.

Can fall, move or slide

A thing with built in generator is that they are properly fastened. A built in generator wouldn’t roll down or have any unsecured area. It will be properly fixed. Same may not be the case with portable generators. You may have it fixed, but a built-in is a “built in”.

Electric hazards

With external generator, it also may not be covered properly and thus, introducing other hazards. A back side placed generator will also need underway connection, increasing electric hazards. This is not the case with built in generator, the wiring and connection cords will be properly insulated.

Fumes, Carbon Monoxide hazard

The portable generator will also produce fumes, carbon monoxide. CO is a odorless, colorless that can be very harmful if proper ventilation is not available.

Built-in generators have exhausts that are release outside and it wont bother in the interior of the RV. Portable generators are meant to be placed outside, away from the RV with exhaust facing in the opposite direction.

Having a carbon monoxide detector helps in identify such CO generation. Whether you run the generator while driving or not, always have a functioning CO detector in your RV.

Looking at all of these safety concerns it is advisable to not run portable generator in an RV while driving down the road.

If you still want to use an portable generator while driving then be sure to do the setup under RV professional expert’s advice. Some people do try such things but you need to be absolutely sure and secure the generator before using it.

Other conditions for running the generator

There are a lot of other situations where we have doubts on whether we can run the generator or not. Here are some of this scenarios.

In a travel trailer

It is not legal to travel in a travel trailer and that makes it clear that you should not run the generator while towing it. Same applies for other towable RV’s.

Can you use it for charging the batteries? Well, this too can be risky and you should avoid it though there wont be any passengers there.

Fire Hazard

Propane run generators should be completely avoided while driving the RV. It is illegal in some states to have propane onboard a running RV.

Also, while at the gas station it is dangerous and also illegal to run a propane appliance or equipment.

You should also avoid running the generator when you are away. Not being around can pose fire risks which can result in burning nearby forest or campground property.

Electrical equipment have unexpected risks of short circuit, blast and therefore being around can help restrict the damage.

In a fifth wheel

It is legal to ride in a fifth wheel in some states but even here same rules apply. Do not run the generator unless it is in-built and also it should be legal to ride in that state. 5th Wheels are often big and luxurious which also means they often come equipped with built-in generators.

While Sleeping

This is an easy to mess up situation. Its never safe to run a generator inside the RV when you are sleeping whole night.

There is a potential of carbon monoxide generation which can be dangerous and therefore you should avoid generator while sleeping.

Apart from this, you should have CO detectors in the RV irrespective of whether you would use the generator or not. CO can be dangerous for health and you should always be vigilant and have all safety features in place.

How long to run and maintenance

Running the generator for too long can also be dangerous. Do not exceed the limits as it can result in CO production and also other fire hazards. Do regular maintenance, this will keep the generator in tip top condition.

Some campgrounds also have defined hours for running a generator. This is done primarily to avoid both noise and exhaust. Even though your generator may be less noisy but you still need to follow the campground rules.

Do not run the generator while you are refueling it. This has a potential to cause fire or even fire and therefore, refrain from refueling or doing any sort of maintenance while the generator is still running.

While the RV is plugged in

You can run the built-in generator while the RV is still plugged in. Whether it will be used to power the appliances or not will depend on the type of transfer switch in place. The transfer switch can be automatic or manual.

With a automatic transfer switch (ATS), the moment you turn on the generator, it will switch to the generator, shutting off the shore power connection.

Incase of manual transfer switch, you need to manual cut off the shore power and transfer it to the generator.

When its raining

Onboard generator inside the RV is safe to run while it pours outside. However, It may not be safe to operate a portable generator with rain or snow conditions as there are chances of electrocution. You also need to properly ground the generator.

Why run the generator While driving

A generator could be running on gasoline, diesel or propane. A built in generator will draw the fuel directly from the rv gas tank.

  • In-built generator can run for days continuously but that is not advisable because it can pose safety concerns. Portable generator can run for 8-20 hours.

The reason why you need a generator in rv is because you will have appliances that would run on 110 V AC.

The main appliances that run on generator are air conditioners, refrigerator, microwave, television etc.

Running Air Conditioner While Driving

AC is the one that you would need while driving. A good roof top air conditioner is something all RVers want to use while hitting the road during hot summer especially, when the temperatures are high above 85-90.

A dash air conditioner can make things cool only up to certain limit. And with passenger on-board, it sometimes becomes necessary that you turn on the roof top air conditioner.

Even when you have pet dogs and cats the roof top air conditioner can be very helpful in keeping the pets happier and calm.


Running air conditioner can be a good thing to do while driving if the generator is turned on. But, using it for refrigerator is not a wise thing to do.

The reason for this, is that the refrigerators may not work well if the RV is not in good leveled positions. That’s the thing with RV refrigerators. They work on absorption mechanism and they need to be on leveled surfaces for proper operation. Other things like microwave or television can also be powered from generator

One can also use inverter and convert the 12 v dc batteries output into 110 v AC, but that may not be sufficient and practical way. Solar power can also be tapped using solar panel on top of RV.

Using solar energy is great but it depends a lot on other factors. Plus, running things like air conditioner and fridge can be a big deal for solar.

Mileage of motorhomes with a running generator

Motorhome mileage is a significant factor. On an average, a motorhome gives close to around 10 mpg. That is less, but with such heavy vehicles this is expected.

Also, when you spend so much buying those bulky road hitters, you ideally shouldn’t be much worried. But, people do watch out for this expenses specially when you are full timer. A miles per gallon calculation is a must for someone who spends travelling almost most months of the year.

So, will running a generator affect the overall mpg of the RV? Generally speaking it wont affect the miles per gallon. But, the fuel consumption will be increased based on how much your generator is consuming. For example if the RV was burning 10 gallons in an hour and the generator took 1 gallon in an hour, your total consumption now is 11 gallons.

To investigate whether the generator affects the mpg of your RV in any way, note down the miles per gallon while running the generator and substract with the normal mpg.

Ideally, a generator in RV would consume depending on the size. A 3500 watts generator would consume lesser as compared to 5000 watts or more.

The gas or diesel consumption is also dependent on the appliances that will be powered by the generator output. A motorhome that runs dual air conditioners also with fridge will need more gas as compared to the one that only runs a smaller air conditioners.

On an average, you should be prepared to spend around a gallon per hour gas for your generator. That’s the average, it could be less or little more too. But, mostly a generator running in rv takes around 0.8-1 gallons of gas per hour.

I have seen people or rather mostly sales people saying that a rv generator would take around 1/4 of gallon per hour. But, mostly i have seen this number to be little higher and at best it can be around 1/2 of gallon. But, with varying conditions the average turns out to be around 0.8 or little above 1 gallon per hour.

With this calculations you shouldn’t be much hit with the overall mileage of the motorhome.

Will generator finish off RV fuel tank?

One good thing about using built in generator in you rv is that, it would automatically shut off when the motorhome tank starts to empty.

If your RV generator stops running while driving then it could be most probably because of the auto shut off feature.

Normally, this level is around 1/4, that is, once your motorhome tank is emptied 3/4th or it is 1/4th full, the generator would automatically shut down.

Now, that’s a very good feature to have. With this, you don’t really have to keep a continuous eye on the fuel level. And, you would not be in position that suddenly the fuel tank is empty and you cant move your motorhome anymore in the middle of the road.

This is an important aspect, because the air conditioner do need lot of power. In fact, they are the ones that consume most watts among all your rv appliances.

Air conditioner and refrigerator, both dictate how much watts of generator you need in your RV. They also have starting watts that are much higher as compared to the running watts.

With all this calculations, the generator would increase the fuel consumption by 1 gallon per hour. That should be fine i guess, considering the comfort you get.

Most people should be good to go with this kind of set up and just not be worried much about increase fuel usage. After all, motorhome is all about comfort and a different living style that includes luxury.

How can you avoid running generator in RV

As we already saw, the main reason why you need the generator is to run air conditioner or refrigerator in some cases.

So, if you want to avoid running generator then make sure to do things that would result in no need of air conditioner or refrigerator.

Refrigerator takes good amount of watts for running and thus you should be careful while using it in rv. I had covered the watts consumption of rv refrigerator in this article.

During non summer seasons, AC may not be needed. Refrigerator need can also be avoided provided you do below things.

  • Keep refrigerator cool enough before starting the journey
  • Use ice bags or ice cubes
  • Don’t open the refrigerator too often before and while in journey
  • Use designated rv refrigerator that works well and stays cool even when not ON

Air conditioners too are heavy on watts (see here the details on ac watts usage in rv) and thus you need to be careful on its usage. During summer season when the temperatures are high, one can still dump Air conditioner and avoid the generator. Do below to avoid AC,

  •  Always park RV under shade
  • Cover windows with sun protective covers
  • Make sure for good air circulation in RV
  • Separate drivers area and passenger area with curtain to avoid sunlight from main windshield screen

Can using generator in rv while driving be a good thing to do?

This is something nobody would be expecting, because the basic question that most people have is “whether they can use the rv generator or not while driving rv”. But, if you analyze a little bit it can provide an advantage to run the generator while driving a rv.

I am not talking about running the appliances. Obviously, that’s why you want to run the generator. You would get nice cool air, an entertainment while on television while driving. You can make that quick sandwich while driving.

A generator is mostly bought or is pre-built so that you could use it more often. A generator that is not used as per recommendations by manufacturer would be a bad thing for it.

It should run for many hours so as to make sure it remains in good working conditions. An under utilized generator will lead to issues and will need early repair. Mostly, you could use it while boondocking and if you don’t like boondocking or dry camping then when would you use it?

At campsites, mostly you would get the electric connection and you may not need the generator at that time. Thus, the overall usage of generator falls and can lead to early failure or may start consuming more gas.

Using the generator while driving can help you in using the generator exactly that many hours. Have seen people who say their generator runs more than their motorhome engine, that is funny to say the least. But, at times people make sure their air conditioner starts to run before they start the journey, that helps to cool it down much better.

what to look for in a generator

It has to be efficient, light weight and most importantly, should produce as minimum noise as possible. You can check this WEN super quite generator on amazon. Its highly rated generator and is also CARB compliant. It weighs under 50lbs which is great for a RV or travel trailer.


One can use a diesel or gasoline run generator in rv provided its a built in one. There can be issues with using external one while hitting the road. Also, generators cannot be used in moving travel trailers or even in fifth wheel it cannot be safe enough as you don’t have direct connectivity. Although, people can travel in fifth wheel but using generator will not be ideal.

G. Yoganand

A RV enthusiast who spends countless hours researching and learning various things related to RV camping. He believes in spending time doing Outdoor activities.
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