How to choose the perfect size generator for your caravan

19/06/2023 By RV Solutions Blog GO BACK

When it comes to powering your caravan off-grid there’s no doubt that a well set up solar power, lithium battery and inverter system is the most convenient, easy and long-lasting power solution. However we understand that a setup like this can be a big investment. If you can’t quite make a solar power system happen, or you need a backup power source, generators are a fantastic option.

With a generator you have a power source that can provide 240v electricity to power your air-conditioning, run a range of appliances and charge your battery system. With such a wide range of generators on the market though, it can be seriously tricky to figure out which one is going to be right for your needs. Here’s everything you need to consider when choosing a caravan; from your caravan size to power needs, to alternative 12v options for popular appliances.

Generators vs Battery Systems

Before we dive straight into our generator tips, first you’ll need to decide if this really is the best off-grid power source for you.

While both power sources have their advantages, battery systems tend to be a more sustainable, quiet, convenient, and environmentally friendly option. Modern battery systems, especially those using lithium batteries, offer impressive energy storage capacities. They can be charged through solar panels which provides a renewable energy source that’s perfect for extended trips off the beaten track. Batteries can also be stored in small, typically unused spaces within your caravan such as under the bed or lounge, allowing you to make the most of the space you’re travelling with. A battery weighs a lot less than a generator, which means investing in a solar system will help you save dramatically on your total payload. Alongside these advantages, if you have enough solar power coming in, and a good-quality battery to store your power, you’ll be able to run even the most power-draining appliances on your battery system, such as air conditioning.

However, if a full solar, lithium battery, and inverter system isn’t a possibility, a generator will definitely do the job. At the heart of it, a generator basically gives you on-demand power. Meaning you get it when the generator is on, but there aren’t any stores (batteries). Though a typical generator can be very noisy and may be banned from some caravan parks, advancements in inverter generator technology have made them quieter and more efficient than ever.

The obvious downside to a generator is that they need to be fuelled—typically with petrol or diesel. This means you’ll need to carry extra fuel in your caravan which you may not otherwise need to bring, adding weight to your overall payload. To avoid carrying unnecessary weight, again we’d recommend going with a solar power and 12v battery system. To learn more about our recommendations for powering your caravan off-grid, check out this blog.

If you have decided that a generator is the most feasible option for you, next it’s time to figure out which type of generator would suit your needs best!

Types of Generators (there’s more than you think!)

Portable power generation has evolved from the typical 4 stroke petrol generator spewing out slightly dodgy AC power, running at full tilt and annoying everyone in a hundred-metre radius. Nowadays you’ve got a range of options that can be a little overwhelming, and the reasons to choose one over another aren’t obvious.

To cut to the chase, among the wide range of generators available, we recommend inverter generators. Inverter generators are quiet, compact and release clean energy, so you won’t need to worry about damaging sensitive electronics. Unless you’re looking for a portable generator with enough power output to run a large motorhome, inverter generators are the best option. Although they might be a bit more expensive than other portable generators, inverters save money in the long run due to their unbeaten fuel efficiency.

But what IS an inverter generator? And what are the other options?

Portable inverter generators: These are lightweight, compact, and fuel-efficient generators that produce clean power for sensitive electronics. They usually run on petrol, but diesel options are available, and have a lower noise output compared to traditional generators. This is because of the way they generate, invert and output the power (more on that later).

Conventional generators: Your typical 4-stroke noisy boy. These generators are larger, more powerful, and far louder than inverter generators. They run on petrol, diesel, or propane (petrol being the most common) and are more suitable for heavy-duty power requirements.

Solar generators: It’s worth mentioning that a solar array with panels, regulators and stores can be considered a ‘solar generator’. Solar generators harness energy from the sun using solar panels, which is then stored in batteries for later use. They are environmentally friendly, silent, and have low maintenance costs. However, their power output is dependent on sunlight (obviously), making them less reliable in overcast conditions. They’re also not anywhere close to the potential output of a petrol generator without a ridiculous amount of solar panels.

Wind generators: These generators use wind energy to produce electricity. Although they are an eco-friendly option, they require a consistent wind speed to work efficiently and won’t not be suitable for all locations. You’ll generally find these on yachts, given the typical windiness of the ocean. They work in theory for caravans, but generally aren’t worth the effort.

Fuel cell generators: Fuel cell generators produce electricity by combining hydrogen and oxygen, with water as the only byproduct. They’re quiet, efficient, and environmentally friendly, but they’re expensive and hard to find (at the moment). Are they available for the average Australian caravanner? Not really. But, they could be soon!

Why Inverter Generators are quieter than Conventional Generators

Inverter generators are generally quieter than conventional generators due to several reasons:

Engine speed regulation: Inverter generators have a smart throttle system that adjusts the engine speed according to the power demand. When the load is low, the engine runs at a lower speed, reducing noise levels. Conventional generators, on the other hand, run at a constant speed (usually 3,600 RPM) regardless of the power demand, which generates more noise.

Size and design: Inverter generators are usually smaller and more compact compared to conventional generators. Because their use-case is more for sensitive electronics, and specifically for caravanners of the modern era, they don’t have to be as beefy as a conventional generator. This means their engines are often designed to be quieter rather than aimed at raw power, and the overall construction includes sound-dampening materials and noise-reducing features, such as mufflers and enclosures.

Advanced technology: The power generation process in inverter generators is different from that of conventional generators. Inverter generators produce AC power, which is converted into DC power and then inverted back to AC power. This process results in a cleaner and more stable power output, reducing the strain on the engine and contributing to lower noise levels.

While inverter generators are generally quieter, it’s essential to note that noise levels may vary between different models and brands. It’s always a good idea to check the manufacturer’s specifications and compare them before making a purchase. Better yet, try to hear one in person!

How To Choose The Right Size Generator.

Say you’ve decided on the type of generator you want for your caravanning power needs, now it’s time to choose the right size. This is where things can get tricky, because while calculating power needs is simple and straightforward, it’s not immediately obvious.

Here’s a simple step-by-step process to understand your power needs.

  1. Calculate the total running watts (your appliances have 2 wattage values, one is how much power it needs to start and the other is how much it needs to run) of all the appliances you intend to power simultaneously.
  2. Find the highest starting watts of those appliances. This will probably be your air-con.
  3. Add your total running watts to your highest starting watts.
  4. Then, find a generator that has a maximum output that’s a little bit higher than your calculated number. You want a little bit of a safety margin, and ideally you want your total running watts to stay under the generator’s ‘rated output’ figure—which is essentially what it’s designed to output over a continuous period of time.

Here’s an example scenario to show you the maths in action.

In this example scenario, you’re camping off-grid in Australia and want to power an air conditioner (AC), a TV, and a fridge simultaneously. Here are some estimated power requirements for each appliance:

Air conditioner: A portable AC unit, such as the Dometic FreshJet 2200, has a cooling capacity of 2.2 kW (2,200 watts) and may require approximately 600 watts of running power and 1,800 watts of starting power.

TV: A small 32-inch LED TV like the Hisense 32″ HD LED Smart TV, typically consumes around 50 watts of running power.

Fridge: A portable camping fridge, such as the Dometic CFX3 55IM, consumes around 65 watts of running power. As a compressor fridge, the starting power can be slightly higher, around 120 watts.

To calculate the generator size, follow these steps:

  1. Calculate the total Running Watts: 600 (AC) + 50 (TV) + 65 (fridge) = 715 watts
  2. Find the highest Starting Watts: The AC has the highest starting wattage of 1,800 watts.
  3. Add the highest Starting Watts to the total Running Watts: 1,800 + 715 = 2,515 watts

Based on this calculation, you’ll need a generator with at least 2,515 watts of output. To be on the safe side and provide some room for additional power needs, consider a generator with a slightly higher output.

A suitable inverter generator for this scenario is the Yamaha EF2800i, with a maximum output of 2,800 watts and a rated output of 2,500 watts. This generator will give you ample power to get everything running and has a little headroom to accommodate any unexpected power requirements or future add-ons to your camping setup.

Example Scenario 2

In this scenario, you’re camping off-grid and everything’s bigger. You want to power a bigger air conditioner (AC), a larger TV, a bigger fridge, charge phones and a laptop, and use lights all at the same time. Here’s roughly what each of those things is going to need to run.

Air conditioner: The Dometic FreshJet 3200 has a cooling capacity of 3.2 kW (3,200 watts) and requires approximately 1,000 watts of running power and 2,800 watts of starting power.

Running a bigger 55-inch LED TV like the Samsung 55″ 4K Smart TV, typically consumes around 100 watts of running power per hour.

A larger portable camping fridge, such as the Dometic CFX3 95DZ, consumes around 100 watts of running power. As a compressor fridge, the starting power can be slightly higher, around 150 watts.

Charging two smartphones might consume about 10 watts each (20 watts total), and charging a laptop is about 65 watts of running power.

Using energy-efficient LED lights, such as a set of four 10W LED lights, would consume around 40 watts an hour.

Let’s calculate those costs.

  1. Total Running Watts: 1,000 (AC) + 100 (TV) + 100 (fridge) + 20 (phones) + 65 (laptop) + 40 (lights) = 1,325 watts
  2. Highest Starting Watts: The AC has the highest starting wattage of 2,800 watts.
  3. Highest Starting Watts + Total Running Watts: 2,800 + 1,325 = 4,125 watts

A suitable generator for this scenario is the Honda EU65is, which has a maximum output of 6,500 watts and a rated output of 5,500 watts. This generator will provide ample power for your larger appliances, devices, and additional power requirements. It also features inverter technology for stable power output, making it suitable for sensitive electronics.

Remember to check the noise levels, weight, and runtime of the generator you choose to ensure it meets your specific needs while camping off-grid.

Other factors to consider when choosing a generator for your caravan.

It’s not all about power output when you’re picking a generator. Here are some important considerations to factor in that might help when deciding between a few different models.

Fuel type: Generators can run on gasoline, diesel, or propane. Consider the fuel availability, cost, and efficiency when making a decision. Gasoline is widely available and often less expensive, but diesel generators are generally more fuel-efficient and have longer lifespans.

Noise level: Noise can be an important factor when camping, especially in shared campgrounds or parks. Choose a generator with a lower decibel rating to minimise noise pollution (and how mad your fellow campers get). We’ve said it a few times already, but inverter generators are quieter than conventional generators, which is a big plus in our books.

Portability: Consider the generator’s size and weight, as well as whether it has handles or wheels for easier transportation. A smaller, lighter generator will be more convenient to move and store, keeping in mind that generators are typically kept in the front tool box.

Runtime: Check the generator’s runtime on a full tank of fuel. Longer runtimes can be more convenient, as you won’t need to refuel as often.

Inverter technology: Inverter generators produce cleaner and more stable power, which is essential for sensitive electronics such as laptops, smartphones, and modern TVs. If you plan on using these devices, we strongly suggest you consider an inverter generator.

Parallel capability: Some inverter generators can be connected in parallel to increase the total power output. This can be a helpful feature if you need more power in the future but don’t want to invest in a larger generator right away.

Maintenance and support: Research the ease of maintenance and availability of replacement parts for your chosen generator. Also, consider the warranty and customer support offered by the manufacturer.

Safety features: Look for generators with built-in safety features such as overload protection, low oil shutoff, and spark arrestors to protect both the generator and your appliances.

Budget: Finally, consider your budget and the generator’s cost. Balance the initial investment with the long-term costs of fuel and maintenance, and choose a generator that offers the best value for your specific needs.

Taking these factors into account will help you find the right generator for your caravan and ensure a pleasant, hassle-free off-grid experience.

Looking for a more advanced power management system?

While a generator can be a great short-term solution to off-grid power, if you’re as mad keen as we are about getting off the beaten track, we can’t recommend upgrading to a solar power system enough! With a good solar setup, you can get off-grid for weeks at a time, without needing to worry about where your nearest fuel station is, or how much extra weight you’ll have to carry.

Here at RV Solutions, we specialise in outfitting your caravan with everything you need to get off-grid for extended periods of time. To learn more about what solar power management system would be best for your caravan, get in touch with our experienced team today, or call in to our Rockingham showroom to have a chat!

Come down, or call us today!

Check out our socials to find out more on recent builds and to keep up to date with us.


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