12V to 240V Inverter Buying Guide (Updated for 2025)
- Chris Wallace-Tarry
- Apr 5
- 14 min read
Updated: 1 day ago
Your 12V to 240V inverter is an essential part of your electrical system. It powers your mains devices from your leisure batteries whilst off-grid, allowing you to work from a laptop, use kitchen appliances, or power a CPAP machine. However, the mainstreaming of off-grid energy has flooded the market with cheap, unreliable inverters that can damage your electrics and won't outlast their short warranties.
I made the mistake of buying a cheap 12V to 240V inverter from a no-name brand for my first van conversion. It was a nightmare; the display was terrible, the fan ran loudly and inexplicably even when I wasn't using the inverter, and the whole thing eventually faulted and died altogether. I swapped the inverter for one with better specs from a reputable brand, and it's been running quietly and reliably ever since.
Beyond choosing an inverter that performs well and stands the test of time, there's the choice between sizes, surge ratings, stated efficiencies, and sine wave type. This article breaks down the inverter buying process, factor by factor. We'll help you size your inverter, choose your key features, and recommend the best inverters and a camper van inverter kit for your chosen size.
If you're just getting started, make sure you read our full guide on inverters. In that article, we go in-depth into how they work, electrical regulations, power factor, and how to install and wire up your inverter.
Index
Shane, the founder of The Van Conversion, is a campervan professional dedicated to helping people transform ordinary vans into homes on wheels. He has authored Roaming Home, and teaches The Van Conversion Course, guiding many people through their van builds. Shane also writes The Van Conversion Newsletter, where he shares practical tips and insights. After completing two van builds and living on the road full-time since 2020, he is passionate about sharing his expertise with others.
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Our Top Picks
If you're anxious to get your inverter ordered, these are our top picks for 12V to 240V inverters. These are all pure sine wave inverters with comprehensive safety features that offer high efficiency ratings.
Best Mid-sized 12V to 240V Inverter
Most vanlifers don't need anything more than 1000W of inverter power. This range allows you to power all your device chargers plus a couple of higher-wattage appliances like a TV, projector, or e-bike charger all at the same time.
Victron's 800W inverter delivers this power at a very affordable price, for which you get Victron's high efficiency, industry-leading build quality, and unparalleled connectivity options.
Best Inverter-charger
An inverter-charger combines an inverter with a shore hook-up mains charger in one package. If you split your time between campsites and off-grid, an inverter-charger saves you money and drastically simplifies your wiring. We recommend Victron's MultiPlus inverter-chargers for their excellent range in sizes and top-of-the-pile reputation.
Best Camper Van Inverter Kit
If you're installing an inverter-charger, you need to support the system with a consumer unit, shore power inlet, and mains wall sockets, plus appropriate wiring and fusing. Sunstore's inverter-charger kit bundles together everything you need for the installation, meaning you don't have to worry about sizing the components yourself.
Sizing Your Inverter
As we discuss in detail in our inverters guide, sizing your inverter is mostly as simple as adding up the wattages of all the 240V appliances you'll be powering at once. 'At once' is the key here; you might look at your 500W blender, 800W toaster, and 100W laptop charger and decide you need a 2000W inverter to power them all. However, by unplugging the blender whilst the toaster's running, you might only need a 1500W inverter.
My 500W inverter powers my various chargers simultaneously without a problem. On the occasion that I want to run my little 350W smoothie maker, I unplug everything else and run it off the same 500W inverter. I saved hundreds of pounds by avoiding the common mistake of adding up all my 240V appliances and assuming I'd need an inverter big enough to power them all at once.
There are a couple of buffers we need to add when sizing a 12V to 240V inverter. To keep things simple, we incorporate a safety buffer of about 30% to account for the inefficiency of certain kinds of electrical load and the fact that loads can fluctuate and spike when devices are first turned on. We also take into account inverter efficiency, which is affected by how much power the inverter itself uses when it's converting from 12V to 240V. We'll discuss inverter efficiency in the next section.
Altogether, our calculation for inverter size takes the total wattage of the 240V devices we'll use simultaneously, adds a 30% safety buffer, and divides the whole thing by the efficiency of our chosen inverter. For an inverter with a 90% efficiency rating, the calculation is:
Total wattage of 240V appliances = 500W
Plus 30% safety factor: 500 + (30% of 500 = 150) = 650W
Divided by inverter efficiency: 650 x 0.9 = 722
Total required inverter wattage = 722W
For this case, we'd recommend this 800W Victron inverter for its quiet operation, high peak power rating, integrated automatic transfer switch, and long warranty.
Our 12V DC to 240V AC inverter sizing calculator does these calculations for you, and even recommends an inverter based on your calculated total power.
12V to 240V Inverter Efficiency
An inverter's efficiency rating reflects the amount of power lost during the 12V to 240V conversion process. In other words, it's the amount of power the inverter itself uses. For example, if an inverter uses 15% of the power it pulls from your batteries to do the inverting, it's running at 85% efficiency. If an inverter only uses 6% of the power it pulls and sends the rest to your devices, then it's 94% efficient.
High-quality inverters are at least 90% efficient, and we wouldn't recommend buying anything with a lower efficiency rating. For example, Renogy's excellent inverters all boast 90% efficiency ratings, and are some of the best inverters for campervan systems.
Victron's inverters are known to be some of the most efficient on the market, boasting 94% efficiency ratings. However, the 4% difference isn't enough to be relevant unless you're buying a really big inverter. Comparing Renogy's 2000W inverter with Victron's, their respective efficiency ratings amount to an 80W difference in Victron's favour. This is enough to power an extra laptop charger. It's up to you to judge whether this is worth the £350 price difference.
Key Features of a 12V to 240V Inverter
The best inverters for campervan systems come with in-built features which differentiate them from their lower-spec competitors. These include:
Built-in Automatic Transfer Switch (ATS): smooth, automatic switching between shore and battery power, useful if you do a mix of campsite living and off-grid
Safety Protections: important automatic safety features which protect your system and your inverter's longevity
Communications and Monitoring: the ability to monitor your inverter's performance and its integration with your other electrical components
Warranty and Support: replacement in case of serious malfunctions
Built-in ATS
An ATS detects when you plug your campervan into a mains outlet and automatically switches the inverter over from battery power to mains. This ensures your batteries charge from the mains connection rather than continuing to power your inverter. Some kind of transfer switch is necessary for any system which incorporates a shore power connection. Separate manual and automatic transfer switches exist and are easy to wire up, but choosing an inverter with a built-in ATS ensures smooth performance, minimal wiring, and an overall simpler installation.
Every Victron inverter and every Renogy inverter incorporates a built-in ATS as standard, meaning you don't have to think about manually switching these inverters over when you plug in at a campsite or rest stop.
Safety Protections
The best inverters for campervan systems incorporate safety features to prevent dangerous malfunctions and protect your leisure batteries. I would never install an inverter in my campervan that didn't have the following protections:
Over-temperature protection: automatically shuts off the inverter in case of overheating due to high loads and high atmospheric temperatures
Short circuit protection: shuts off the inverter in case of a short circuit in an unfused part of your system
Over-load protection: automatically shuts off the inverter in case the load from your devices is too high, preventing overheating, fires, and explosions
Under- and over-voltage protection: shuts off the inverter if your leisure batteries go into a voltage range that would damage them or the inverter
Again, every Victron inverter and every Renogy inverter incorporates all of these safety features, which is another reason we recommend these inverters over other manufacturers.
Communications and Monitoring
It's useful to be able to monitor your inverter's function as it runs to see how much power it's pulling from your batteries and how much load your devices are putting on it. Additionally, the advanced features of certain inverters, like automatic cut-off levels, eco mode parameters, and variable output frequency, are more easily tinkered with on your phone or computer.
This is where inverter connectivity comes in. Plugging a VE.Direct Smart Dongle into your Victron inverter allows you to connect to it by Bluetooth, giving you easy monitoring and control.
Renogy's inverters have the same capability with the addition of the BT-2 Bluetooth module.
In addition to Bluetooth monitoring of your inverter, Victron take things a step further with their 'interconnected ecosystem'. Every device, including your Victron inverter, shares common communications outputs. This allows you to connect your inverter to your battery monitor system, allowing your inverter to see your battery's state of charge and tailor its power draw accordingly.
You can take this one step further by connecting all of your Victron devices to a GX device like the Cerbo. The Cerbo collects information on all of your electrical components and displays it as an integrated dashboard on-screen or in the remotely-accessible VRM. This way, you can monitor your whole system's status and performance in real-time, seeing how all of your components interact. You can also see historical data like power usage over time and solar production visualised as graphs, and set up rules and settings for your entire integrated system.
This interconnectivity isn't necessary, and it won't noticeably change your system's efficiency. Instead, it's about being able to see the performance of all your components in one place. This makes for better troubleshooting, a crystal-clear understanding of how your system works, and lots of nice data to get nerdy over. If this sounds like something you want, a Victron inverter wired into a Victron electrical system is the only way to go.
Warranty and Support
When choosing a 12V to 240V inverter, it's worth considering the warranty and the manufacturer's reputation for support. Any manufacturer that believes in the quality of their product will provide at least a 1 year warranty. Additionally, a dedicated, trustworthy support service gives you the confidence that if your inverter dies, you won't be left high and dry.
This is where Victron again takes the crown. They offer 5-year warranties on their inverters, and have a reputation for strong technical support. Renogy's 1 or 2-year warranties don't compare, and their support isn't as well-regarded. If you're willing to pay the premium for peace of mind, Victron put their money where their mouth is.
Modified vs. Pure Sine Wave Inverters
The final piece of the puzzle is the kind of electrical sine wave that your inverter produces. As we explain in our comprehensive guide to inverters, an inverter takes DC electricity and converts it to AC by imitating the undulating sine wave that an AC power supply provides. Depending on the quality of the electronics, an inverter may produce either a modified sine wave or a pure sine wave.
A pure sine wave inverters give us much 'cleaner' electricity. This means a smooth wave that closely matches the actual sine wave of AC electricity. A modified sine wave is an approximation of a sine wave comprised of square steps. In practice, the benefits of a pure sine wave inverter are:
No risk of damage to sensitive electronics (computers, consoles, TVs, CPAP machines)
No buzzing from audio equipment
No sync problems with digital timers or clocks
Perfect functioning of dimmer switches and variable power dials
Smooth, efficient operation of inductive appliances (motors, fans, induction hobs)
No overall damage to a device's lifespan
Respectable manufacturers only produce pure sine wave inverters today, in recognition of the fact that even everyday devices can be damaged by a modified sine wave. This is another reason we recommend Victron and Renogy: all of their inverters are pure sine wave as standard.
The Best Inverters for Campervan Systems
Besides Renogy and Victron, we'll also be discussing NDS and Sterling inverters here. I have a Renogy inverter in my van, which I chose mostly due to the balance between cost and quality. Shane has an all-Victron system, which he loves for the interconnectedness and smart monitoring. Neither of us has had issues with our inverters, which are essential for doing our jobs remotely. NDS inverters are well-established in the European market, and their wide range of pure sine wave inverters are notable for their compact form factors. Sterling are a British manufacturer, whose long history in the marine industry means their inverters are extra rugged and reliable.
Best Small 12V DC to 240V AC Inverter: Victron Phoenix 375W
Many vanlifers' only 240V appliances are laptop chargers. Most other consumer devices, even up to portable projectors and drone chargers, can run off 12V power via a 12V USB socket. If this is your case, you don't need anything more than a 375W inverter.
In this category, the 375W Phoenix Victron inverter is the clear winner. At a low price, you get all of Victron's premium build quality, efficiency, and remote monitoring capabilities, plus a 5-year warranty.
Runner-up: NDS Smart-in 400W Inverter
NDS is a well-established European manufacturer of campervan electronics which has been brought under Dometic's umbrella. They make both pure and modified sine wave inverters, and are known for their very small form factors. NDS'' 400W pure sine wave inverter has great peak power and efficiency ratings and packages everything up in a very compact, lightweight device.
Runner-up: Sterling Pro Power SB 300W Inverter
Sterling are a very well-established UK manufacturer who have been in the marine industry for years. Their inverters are known for their rugged reliability in tough marine environments.
Best Mid-sized 12V to 240V Inverter: Victron Phoenix 800W
An 800W-1000W inverter can power most device combinations that you find in a campervan. With an inverter of this size, you could use a higher-wattage kitchen appliance like a blender without having to unplug your laptop or TV.
Victron's 800W offering takes the crown again here. It's top-flight efficiency and zero-load power can't be argued with. Combine that with unparalleled connectivity, an exemplary reputation backed up by a long warranty, and an affordable price, and we'd feel silly recommending anything else.
Runner-up: Renogy 1000W Inverter
A more affordable 12V to 240V inverter in this range is Renogy's 1000W inverter. It incorporates high-efficiency, pure sine wave operation and all the essential safety features, but sacrifices a long warranty and advanced ecosystem connectivity.
Runner-up: NDS Smart-in 1000W Inverter
NDS' 1000W option has a very high surge power rating, slightly higher efficiency than the Victron inverter, and decent zero-load consumption. It generally scores at least average on all relevant metrics, but this overall performance might not justify its comparatively elevated price.
Runner-up: Sterling Pro Power SB 1000W Inverter
Sterling's 1000W inverter is the lightest and of the lot and very compact, making it great for installation in small cubbyholes (check out Sterling's optional wired remote for easy control if you install your inverter somewhere out-of-the-way). Besides this, you get Sterling's marine-grade ruggedness, albeit with more lacklustre specs elsewhere.
Best Large 12V to 240V Inverter: Victron Phoenix 3000w Smart
Any inverter bigger than the above examples is only necessary if you're powering really high-power appliances. This might be an all-electric campervan with induction hob cooking, or a luxury situation where home comforts like hair dryers and kettles are essential. Family trips with multiple laptops, a games console, a television, and a coffee machine might also make an inverter of this size necessary.
In this case, we recommend Victron's 3000W Phoenix. It's the biggest and bulkiest of the lot, but this is outweighed by a premium feature set plus built-in Bluetooth connectivity at a great price for the capacity.
Runner-up: Renogy 3000W Inverter
Renogy's 3000W inverter has an impressively low price without sacrificing too much to Victron's specs. It incorporates high-efficiency, pure sine wave operation and all the essential safety features. It's also very compact for its size and compatible with Renogy's Bluetooth dongle, but sacrifices a long warranty and advanced ecosystem connectivity.
Runner-up: NDS Smart-in 3000W Inverter
NDS' 3000W option has a very high surge power rating and is nearly as small as the Renogy. It matches Victron's excellent efficiency rating but again falls short on zero-load power and connectivity options.
Runner-up: Sterling Power SB 3000W
Sterling's 3000W inverter is the lightest of the lot, which is valuable in a category of big, heavy inverters. The zero-load power usage is decent for the capacity, but the inverter falls short on efficiency, bulkiness, and peak power rating.
Best 12V to 240V Inverter Charger: Victron Multiplus
An inverter-charger is an all-in-one device that combines a power inverter for van electrics with a shore hook-up battery charger. These combo units are perfect for vanlifers who spend time both off-grid and plugged in at campsites. By installing an inverter-charger, you drastically simplify the installation and operation of your electrical system, cutting down on wiring and fusing and removing the need for a transfer switch.
We have to recommend Victron's Multiplus inverter-chargers here, as the standard model comes in a wide range of sizes and voltages, from 500W to 1600W and from 12V to 48V. The Multiplus range are as efficient as inverter-chargers get, boast incredibly low zero-load consumptions, and integrate fully with Victron's remote monitoring ecosystem.
Runner-up: Renogy Pure Sine Wave Inverter-Chargers
Renogy currently make a 2000W and a 3000W inverter-charger, which boast excellent efficiency ratings and low zero-load consumption figures, whilst offering Bluetooth connectivity with Renogy's Bluetooth dongle. The price points are very budget-friendly, but reflect Renogy's short warranty period.
Best Camper Van Inverter Kit
Buying a power inverter for van use isn't necessarily as simple as just buying the device itself. If you're installing both an inverter and shore power, you also need an appropriate AC consumer unit, a mains inlet, a mains plug socket, plus correctly-sized wiring and fuses. A camper van inverter kit contains all of these components, all sized so that they'll work together. Check out Sunstore's inverter-charger kit, and take some of the headache out of your installation.
Final Thoughts
You should now feel fully equipped to size and choose your 12V to 240V inverter. When you're ready to take the plunge, take a look at our recommended inverters from Victron and Renogy's range, or go for an easy-to-install inverter-charger kit. If you need more information on inverters before buying yours, our comprehensive guide should answer all your questions.
Don't forget to subscribe to The Van Conversion Newsletter for everything you need to get started with your own van conversion (we'll send you a free wiring diagram when you join).
If you're looking for some guidance with your van conversion, you might be interested in our book Roaming Home, or in our online course The Van Conversion Mastery Course. You'll learn directly from our founder Shane how to convert a van into your dream home - no prior experience needed. Shane also offers one-to-one consultations, where he'll help you with any aspect of your build in a face-to-face video call. All consultations come with a free copy of Roaming Home and our Diagram Pack.
Finally, our Van Conversion Ultimate Guide lays out the whole van conversion process in easy-to-follow sections with tools, materials, and step-by-step instructions. It's the perfect companion for your van build.
Until next time.