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Quick answer: For most tourers a 1000–1500W pure sine wave inverter is the sweet spot, with enough grunt to run a pod coffee machine, a toaster or a laptop charger without bullying the battery. Drop to a 300–600W unit if you only top up devices, step up to 2000–3000W for an induction cooktop or microwave, and keep a modified sine wave inverter only for simple resistive gear like a work light or a drill charger.
An inverter turns the 12V sitting in your battery into the 240V your kettle expects, and that one conversion is what lets a vehicle feel like a small flat instead of a campsite. The part nobody mentions at the counter is that the inverter is rarely the weak link. Ask it for 2000W and it will happily pull around 170 amps, and it is the battery bank and the cable feeding it, not the shiny box on the shelf, that decides whether you get coffee or a flat cell and a shutdown.
So the real decision is not how many watts in isolation, but matching a sensibly sized pure sine wave inverter to the battery, cable and fusing behind it. Get that pairing right and you can run genuine household gear a long way from a powered site. Get it wrong and you buy a 3000W unit that trips every time the microwave kicks in. This guide sorts the types, the sizing, and the mistakes that leave people stranded with dead batteries.
Quick Picks
- Best overall: a 1000–1500W pure sine wave inverter for everyday appliances.
- Best for device charging: a compact 300–600W pure sine unit that sips power.
- Best for cooking: a 2000–3000W high-output pure sine inverter.
- Best for a permanent build: an inverter-charger that combines mains charging and 240V output.
- Best budget, limited use: a modified sine wave inverter for resistive loads only.
How to Choose an Inverter
Start with the appliance that pulls the most, not the tally of everything you own. Add the continuous draw of whatever runs at once, then leave roughly 20 per cent headroom so the unit is not sweating at its ceiling all day. The number that catches people out is surge: a microwave or anything with a motor demands a brief spike well above its running figure, so a 1000W microwave can want closer to 1800W for a second at start-up. A good pure sine wave inverter states both a continuous and a peak rating, and you size to the continuous one.
Pure sine wave is the sensible default now, and the price gap has shrunk to the point where modified sine wave only makes sense for basic resistive gear. Brands like Victron, Enerdrive, Redarc, Renogy, Projecta and Giandel build pure sine units across the range, and the ones worth paying for share a low idle draw, temperature-controlled fans that only spin when needed, and a proper stack of protections: low-voltage cut-out, over-temperature shutdown and short-circuit protection.
Then look behind the inverter, because that is where the money is well spent. A large inverter needs a battery bank that can deliver the current without its voltage sagging, which in practice means lithium or a healthy pair of deep-cycle cells, short runs of thick cable in the 0 to 2 AWG range, and a mega fuse or Class-T fuse within a few centimetres of the positive terminal. Skip the fuse and a chafed cable becomes a fire; skimp on the cable and the inverter browns out under load. Have a quick look at the current and most recent options on Amazon for the caravan inverter.
The Inverters
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Compact 300–600W Pure Sine Inverter
This is the quiet achiever for anyone whose 240V needs are really just a laptop that will not charge over USB-C, a camera battery, or a set of clippers. A 300 to 600W pure sine unit draws little at idle, runs cool, and can hang off a modest battery without special cabling. It will not boil a kettle, and that is fine; it is the inverter you fit and forget. Giandel and Renogy both do tidy units in this bracket. Have a quick look at the current and most recent options on Amazon for the 600W pure sine inverter.
Mid-Size 1000–1500W Pure Sine Inverter
The sweet spot for most builds. A 1000 to 1500W pure sine inverter covers the appliances people actually miss: a pod coffee machine, a toaster, a blender, power-tool chargers and a laptop, run one at a time. It is the size that rewards a lithium battery and decent cable without demanding a full rewire of the vehicle. If you buy once and want it to suit the way most people tour, this is the band to shop in. Have a quick look at the current and most recent options on Amazon for the 1500W pure sine inverter.
High-Output 2000–3000W Pure Sine Inverter
Once an induction cooktop, a microwave or a hair dryer is on the menu, you are into 2000 to 3000W territory, and the rules change. This tier genuinely demands lithium, heavy short cable and serious fusing, because the current draw is brutal. Victron and Enerdrive units at this size are built for permanent installs rather than a plug-in-and-hope job. Buy it only if you will actually cook with it, since it is heavier, dearer and thirstier at idle. Have a quick look at the current and most recent options on Amazon for the 3000W pure sine inverter.
Inverter-Charger Combo
For a caravan or a fixed fit-out, an inverter-charger rolls two jobs into one box: it inverts to 240V off-grid, and when you plug into mains it flips to charging the battery and passing power through. Victron’s MultiPlus and Enerdrive’s ePOWER range are the familiar examples. It is neater, saves a second unit, and suits anyone wiring a proper system rather than trailing a lead to a portable inverter. The trade-off is cost and the fact you really do want it installed by someone who knows the wiring. Have a quick look at the current and most recent options on Amazon for the inverter charger.
Modified Sine Wave Inverter
The honest use for a modified sine wave inverter is narrow: simple resistive loads with no clever electronics, like an incandescent work light, a basic drill charger, or an old soldering iron. They are cheap and light, which is the whole appeal. What they are not is safe for sensitive gear, and running a laptop, a CPAP machine or a variable-speed tool off one invites buzzing, heat or a dead appliance. Buy it with clear eyes about that limit. Have a quick look at the current and most recent options on Amazon for the modified sine wave inverter.
Comparison
| Inverter | Continuous power | Typical loads | Battery bank you’ll want |
|---|---|---|---|
| Compact pure sine | 300–600W | Laptop, camera, clippers | Modest, standard cabling |
| Mid-size pure sine | 1000–1500W | Coffee machine, toaster, tools | Lithium or good deep-cycle |
| High-output pure sine | 2000–3000W | Induction, microwave, dryer | Lithium, heavy cable, big fuse |
| Inverter-charger | 1000–3000W | Whole-of-van 240V | Installed lithium system |
| Modified sine | Varies | Resistive loads only | Any, but limited use |
Frequently Asked Questions
What size inverter do I actually need?
Size it to the biggest thing you will run at once, plus about 20 per cent, and check the surge figure as well as the running watts. Charging devices wants a few hundred watts; a kettle, microwave or induction cooktop wants 2000W or more. Buying bigger than you need just wastes idle power and stresses the battery.
Will a 2000W inverter run an air-conditioner?
Usually not a standard one, because the compressor’s start-up surge can spike far past the running figure and trip the inverter. Small inverter-style or soft-start air-conditioners are the exception. If cooling is the goal, size for the surge, not the label, and be honest about what the battery can sustain for hours.
Pure sine or modified — does it really matter?
For anything with a microprocessor, a variable-speed motor or a delicate charger, yes. Modified sine wave can make gear buzz, run hot or fail outright. Pure sine wave mimics mains power and is the safe default now that prices have closed up. Keep modified sine only for simple resistive loads.
Can I run it off my starter battery?
For anything but a tiny inverter, no. A big draw flattens a crank battery fast and can leave you unable to start the vehicle. Run inverters from an auxiliary or dedicated house battery, ideally lithium, fed through a DC-DC charger, and keep the starter battery for its one job.
The Bottom Line
Buy the inverter for the way you actually cook and work, then spend the rest of the budget behind it. A 1000 to 1500W pure sine unit suits most people, a compact 300 to 600W unit is plenty if you only charge gear, and the big 2000 to 3000W units earn their keep only if you genuinely cook with them. Whatever the size, the battery, cable and fuse decide whether it delivers or disappoints, so size those to match and it will run clean 240V for years.
Related: dual battery monitors and jump starter packs.