The New RVers Guide to Generators

…or perhaps a better title is: “HOW TO MAKE MARGARITAS IN THE DESERT”.

Author’s Note: A version of this article was featured in RV Magazine in the August 2021 issue. I write regularly for RV Magazine.  To subscribe, CLICK HERE. (And don’t forget to use code FitRV25 for 25% off!)


I should probably mention that we don’t have a generator in our own RV, and we don’t travel with a portable one.  It’s possible to get most of the functionality of a generator with a large (Lithium) battery bank and inverter, and that’s what we do.  But large Lithium battery banks are far from the norm, and they’re still pretty expensive.  So if you don’t like to live on the bleeding edge of RV tech, a generator is a lot more conventional option for many RVers.  That’s why I tackled this subject in my RV Magazine column.

If you like to camp far away from RV parks or any hookups, and if your chosen comforts require electrical power – like a blender for frozen margaritas – a generator just might be in your RVing future.  Generators provide 120 volt AC power to your RV, just like the power at home, or when your RV is plugged in to shore power. But unlike being plugged in, a generator can provide that power literally anyplace you can take your RV. Simply turn on the generator and presto! Air conditioning, blow dryers, and frozen beverages are yours to command.

There’s a lot to know about generators. And the first thing you might be asking is:


The answer to that question depends on your camping style. If your RV spends most of its time in full-hookup RV sites, you may not need a generator at all. The shore power should provide all the electricity your rig will need. Generators shine the farther away you get from shore power and civilization. So if you like to boondock (or dry camp), and if you don’t have a massive battery bank in your RV that can handle your electrical needs, generators become more important.

The other thing to consider is the 120 volt appliances you’ll be running. Air conditioning is almost always the big driver here, but if you chase 70 degree days and cool nights, that might not be much of a consideration. If your phone charger is the only thing you keep plugged in, you might not need a generator. But if you RV with an instant pot and blow dryer, you’ll probably want one.

A final consideration is your battery capacity. A generator can also charge your RV’s batteries. Many people will run their generators for a few hours each day to charge their batteries, and then shut them down for the evening. If you like to go to bed with full batteries, a generator can help get you there.


Many motorized and some towable RVs come with a generator built in, or at least available as an option. This is a very convenient way to roll.

A generator included with a motorhome will typically draw its fuel from the same tank as the motorhome’s chassis until the fuel tank nears ¼ full. Then the generator will shut down to prevent you from draining the fuel tank unintentionally. Besides the fuel, a built-in generator will also be wired into the RV’s electrical system by the coach builder. This is done either through a manual plug-in, or something called an automatic transfer switch.

Built-in generators are super-convenient, as they can usually be started from a switch inside the RV. The main disadvantages of a built in generator are that your choices are limited, and if your generator needs service, you’ll have to take the whole motorhome in along with it.

Portable generators, on the other hand, are not attached to your RV, so you can take them in separately for service. Or, you can use them with a second RV, or even as backup power for your home.

There are also many more choices in brands and technologies among portable generators.

Portable generators will be hooked up to your RV with a shore power cord. If you purchase a long enough cord for the hookup, you can locate the generator away from your campsite. Whereas with an built-in generator, well, it’s always right there in camp with you. But that portability can also be a generator’s main liability. Portable generators can be an attractive item for thieves, so it makes sense to consider security if you’re thinking of bringing a portable generator along.


There are three main fuel sources for RV generators: Propane, Gasoline, and Diesel. There are advantages and disadvantages to each. Most generators operate on one fuel source only, but there are some models that can operate on both propane and gasoline. Generally speaking, propane generators are the smallest and least powerful of the three, and diesel generators are the largest and typically most powerful. Gasoline generators fall somewhere in the middle.

If you’re looking at portable generators, the type of fuel it uses will be a decision you need to make. (Portable diesel generators are rare, but you can find them.) But if your motorhome came equipped with a generator, it likely uses the same fuel source as your motorhome’s chassis.


Generators are sized in watts. You can find portable generators as small as 1000 watts, and the larger diesel generators can be as much as 12,500 watts, so there’s quite a range to choose from. Built-in generators on motorhomes are usually sized to match the capacity of the coach. For example, a motorhome with a 30 amp shore power connection can handle up to 3600 watts of power, so a generator for this coach could be in the 3000 watt range and handle most of the electrical needs. Whereas a luxury diesel pusher might have 3 air conditioners and warrant the 12,500 watt model – which can supply every bit of what a 50 amp shore power connection can.


A good way to figure the size generator you need is to add up the wattage requirements of all the 120 volt appliances you want to run simultaneously. If you need to run an air conditioner (2000 watts), the microwave (1000 watts), a blow dryer (1500 watts) and your entertainment system (400 watts) at the same time, simply add them up. In this case, you’d come up with 4,900 watts. This is where you may have to negotiate with yourself. The price and size of 5000 watt generators might make you consider shutting off the microwave and TV while you run the blow drier. That would bring your needs down to 3000 watts, which might be enough for you.

When considering generator capacity, you also need to consider the additional load needed to start some appliances – like an RV air conditioner. Air conditioners take more power to start running than they need to stay running. If you purchase too small a generator, it may have trouble starting your air conditioner.


If you peruse the generator aisle, you’ll see two distinct types of generators. Conventional and Inverter generators. If you think of the small, quiet, ultra-portable Honda generators that are very popular – that’s an example of an inverter generator. And if you think of a traditional generator-inside-a-metal-frame, or perhaps a generator included with a motorhome – those are conventional generators.

There are many technical differences between the two types that would take a book to explain. So I’ll oversimplify here and say that in an inverter generator, the final output power is governed by electronics, so the engine doesn’t need to run at a constant speed. And in a conventional generator, power is output directly as AC, and the engine needs to run at about 3600 rpm all the time.

That’s all fine, but what does it mean to an end user? Well, due to the way it generates power, the inverter will produce a more consistent or “clean” power, so it will be better for sensitive electronics. Inverter generators are more fuel efficient, but conventional generators produce more power for less money. And inverter generators are smaller and more portable, but conventional generators generally have larger fuel tanks.

But the biggest difference you’ll notice between the two is that inverter generators are FAR QUIETER than conventional ones. The difference is significant: you’ll notice, and your campground neighbors will appreciate it. If you’re camping by yourself, this may not be a consideration, but if you’ll be camping where there are noise regulations, like in US National Parks, this may be something you need to consider.


Whatever type or model of generator you get, it will have an engine. And just like anything that has an engine, your generator will require periodic maintenance to keep it running properly. The good news here is that they don’t require constant attention. Some basic maintenance is enough to keep them purring along.

You can’t use miles to keep track of maintenance. You’ll need to track hours on the generator. For RVs with built in generators, there should be an hour meter somewhere inside, typically on the same panel you start the generator from. For portable generators, they may or may not come with an hour meter directly on the generator – a feature to consider as it will help keep you honest with maintenance. If there is no hour meter, sometimes there will be indicator lights for oil changes, or perhaps an hour meter will be available as an accessory after purchase. As a last resort, there’s always your watch and a log book!

However you keep track of the hours on your generator, the general maintenance tasks aren’t surprising. Depending on your generator, they may include oil changes, filter changes, and spark plug changes. The recommended maintenance intervals will vary by model, so it’s always best to consult your owner’s manual for the schedule for your generator.


By far, the biggest maintenance issue with generators is lack of use. In a gasoline generator, the fuel can break down and start to varnish in as little as one month. A generator that sits idle can also build up moisture and lose internal lubrication. So for these and more reasons, it’s recommended to “exercise” your generator at least monthly.

The good news is that regular use counts as exercise! Exercising your generator isn’t difficult (see the section below for details) and is probably the most critical thing you can do to keep your generator purring along smoothly for years to come.

So that’s the skinny on generators. Lots of different options, but they all aim to accomplish the same thing: to provide you reliable AC power – and frozen margaritas – just like at home, regardless of where your RV travels take you.


Exercising your Generator

If it’s been more than a month since you’ve run your generator, use these tips to get your generator the exercise it needs:

  • Make sure it’s safe to operate your generator, there’s no debris accumulated around it, and the exhaust is directed safely away.
  • Start your generator, and let it run for 2 hours, at 50% load. What’s 50% load? Take the wattage rating of your generator, and divide by 2. So if you have a 4000 watt generator, you’ll need to run a 2000 watt electrical load. This can be the air conditioner, an electric furnace, or any other appliance that can run continuously for 2 hours.
  • It’s better to exercise your generator for a longer period than a shorter one, and with more load than less. So don’t worry if you go longer than 2 hours, or if your load is more than 50%.

2 thoughts on “The New RVers Guide to Generators

  1. James David McWhite

    Hi James, I just invested in a Bluetti battery back up system for emergency reasons at my home. I’ve even made it EMP shielded. Their latest series (AC300 + multiple B300 power packs), I believe it can revival or surpass your fantastic battery plant you added to you RV (PS I loved your videos, well done).
    It’s ability to recharge it self via so many methods, and ganged with two AC300 can even provide 220 v AC using their home junction box. Makes the need for a gas/diesel or LP generator seem a thing from the past. Solar recharging has leaped way ahead and running a DC charger from your car’s generator sees a no brainer for a RV. Take a look at their top end systems, and I would love to hear your pros and cons as compared to your Lithium system you installed. Take care, keep doing what your doing, and I’ll keep watching.

  2. Kevin Scarbel

    If Honda would decide to target the RV segment, and if Winnebago was savvy, the later could become the exclusive RV brand offering Honda built-in generators. It would be a game-changing sales marketing opportunity.


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