Campervan Inverter Guide: 230V AC Power for UK Van Conversions (2025)

An inverter converts your 12V battery power into 230V AC mains electricity. It's what lets you plug in a laptop, run a Nespresso machine, charge camera batteries, or use a hair dryer — without being connected to a campsite hook-up.

Not every van needs one. But for anyone who works remotely, wants a proper coffee machine, or has appliances that don't have a 12V alternative, it's essential. This guide covers everything: whether you need one, what type to buy, how to size it correctly, how to wire it safely, which appliances you can actually run, and what the realistic limits are.

For the complete system context, see our campervan electrical system guide.

Do You Actually Need an Inverter?

This question is worth taking seriously. Inverters add cost (£150–£600), weight (2–8kg), standby power draw (5–20W), and installation complexity (very thick cables, separate fusing, RCD protection). If you don't genuinely need one, your system is simpler and more efficient without it.

You don't need an inverter for:

• LED lighting (12V)
• Compressor fridge (12V)
• Diesel heater (12V)
• Water pump (12V)
• USB charging — phones, tablets, cameras, most modern laptops with USB-C charging
• 12V water heater
• Fan heater (12V alternatives exist)

You do need an inverter for:

• Laptops that don't support USB-C charging (older MacBook Pro, certain Dell/HP models)
• Nespresso or pod coffee machines
• Bean-to-cup coffee machines
• Hair dryer, hair straighteners, curling tongs
• Electric induction hob
• Microwave (only practical with shore power or large battery + inverter)
• Traditional kettle (though 12V kettles exist)
• Power tools (drill, jigsaw, sander)
• CPAP machine (some models have 12V DC adapters — check yours)
• Any appliance that only comes with a UK 3-pin plug

The USB-C laptop question:

Most laptops manufactured from 2018 onwards support USB-C PD (Power Delivery) charging. A MacBook Air, MacBook Pro (M-series), Dell XPS, ThinkPad, HP Spectre, and most other mainstream laptops now charge via USB-C at 45W, 65W, or 100W. A quality 100W USB-C GaN charger (Anker, Ugreen, Baseus) plugs into a 12V USB socket in your van and charges your laptop directly — no inverter needed.

Check your laptop's charging cable before assuming you need an inverter. If it uses USB-C, you almost certainly don't need an inverter for the laptop alone.

Pure Sine Wave vs Modified Sine Wave

This is the most important technical distinction in inverter selection and it's non-negotiable.

What the Waveforms Mean

Mains electricity from the grid is a smooth, continuously varying AC waveform — a true sine wave at 50Hz in the UK, peaking at approximately 325V (the mains voltage is 230V RMS, which corresponds to a 325V peak). Every appliance that runs on mains power is designed around this waveform.

Pure sine wave inverters produce a true, smooth sine wave — essentially identical to grid power. Every appliance works correctly.

Modified sine wave (MSW) inverters produce a stepped approximation of a sine wave. The waveform is technically AC at 50Hz, but instead of a smooth curve it steps up, holds, steps down — a blocky approximation. It works for simple resistive loads (incandescent bulbs, basic heaters) but causes problems with anything more complex.

What Modified Sine Wave Damages or Degrades

Laptops and electronics: Modern switch-mode power supplies (the "bricks" in laptop chargers and USB chargers) can operate on modified sine wave, but they run less efficiently, generate more heat, and experience more stress on their internal components. The practical risk is reduced lifespan and, in some cases, immediate incompatibility.

CPAP machines: Some CPAP machines simply won't run on modified sine wave. Others run but produce audible noise from their motors. CPAP manufacturers universally recommend pure sine wave.

Microprocessor-controlled appliances: Washing machines, dishwashers, modern refrigerators — any appliance where a microprocessor controls a motor — may malfunction or show fault codes on modified sine wave.

Audio equipment: Modified sine wave introduces a 50Hz hum (and harmonics) into audio equipment. Speakers, amplifiers, and music playback equipment will produce audible buzz.

Battery chargers: The internal transformers in some battery chargers run hot on modified sine wave and can fail prematurely.

Electric motors: Induction motors (used in tools, fans, pumps) run less efficiently and hotter on modified sine wave. Reduced efficiency = wasted energy.

LED dimmers: Many LED dimmer switches are incompatible with modified sine wave.

The Verdict

Always buy pure sine wave. The cost difference between a quality modified sine wave inverter and a quality pure sine wave inverter at the same power rating is typically £50–£100 — negligible in the context of a van build. The compatibility risk with modified sine wave is not worth it.

The only scenario where modified sine wave is acceptable: running a simple resistive load like a basic incandescent lamp or a simple heating element with no electronic control — and even then, a pure sine wave inverter would work just as well.

Understanding Inverter Power Ratings

Every inverter has two power ratings that are frequently confused:

Continuous Power

The wattage the inverter can deliver indefinitely without overheating or shutting down. This is the number that determines whether an appliance will run. A 1,000W continuous inverter can power any combination of loads up to 1,000W without issue.

Peak (Surge) Power

The wattage the inverter can deliver for a brief period — typically 2–3 seconds. This matters for appliances with motors, which draw significantly more current at startup than during steady-state operation.

Startup current examples:

For a power drill with a 500W steady-state draw and a 1,500W startup surge, you need an inverter with at least 500W continuous and at least 1,500W peak — a 1,000W continuous / 2,000W peak inverter would handle this.

Most inverters have a peak rating approximately double their continuous rating. A 1,000W inverter typically peaks at 2,000W.

Power Factor

Some loads draw more power than their simple watt rating suggests, due to power factor. Pure resistive loads (incandescent bulbs, heating elements) have a power factor of 1.0 — they draw exactly their rated watts. Reactive loads (motors, transformers, switch-mode power supplies) have a power factor below 1.0, meaning they draw more apparent power (VA) than their watt rating suggests.

For sizing a campervan inverter, this is usually a minor consideration — most small appliances in campervan use have power factors close to 1.0. The exception is large motor loads like induction hob inverters (some have power factor correction; check the spec). If in doubt, add 20% to the calculated wattage when sizing the inverter.

How to Size Your Inverter

The Sizing Process

1. List every 230V appliance you want to run
2. Note the wattage of each (check the label or spec sheet — not the plug fuse rating)
3. Identify the highest wattage single appliance
4. Consider which appliances you'd run simultaneously (coffee machine + laptop = 1,100W + 65W = 1,165W peak demand)
5. The inverter's continuous rating must exceed your peak simultaneous demand
6. The inverter's surge rating must exceed the startup surge of any motor loads

Inverter Size Guide by Use Case

Don't oversize unnecessarily. A 2,000W inverter on standby when you only need it for a laptop draws more quiescent power than a 300W model. If your genuine maximum load is 600W, a 1,000W inverter with a comfortable margin is better than a 3,000W model.

The Battery Reality Check

An inverter doesn't generate power — it converts battery power from 12V DC to 230V AC. Inverters are approximately 85–92% efficient, depending on load.

Current draw formula: Battery current (A) = Inverter load (W) ÷ (Battery voltage × efficiency)

Example: 1,000W inverter running at full load: = 1,000 ÷ (12 × 0.90) = 92.6A from the battery

At 92.6A continuous, a 200Ah LiFePO4 battery would last approximately: = 200Ah × 0.80 usable ÷ 92.6A = 1.73 hours

This is the constraint that matters. Big loads require big batteries.

Practical inverter energy table:

Induction cooking is possible with battery power, but only with a large battery bank (300Ah+) and awareness that cooking significantly depletes the battery. In practice, many van lifers use a gas hob for cooking and reserve the inverter for smaller loads. See what can a 2000W inverter run in a campervan for a complete load analysis.

UK Product Recommendations

Victron Phoenix (The Reference Standard)

The Victron Phoenix range is the most popular inverter choice for UK campervan builds. Pure sine wave, available in 250W to 5,000W, excellent build quality, and integrates with the Victron ecosystem.

The 1200VA (1,000W continuous) covers most van life needs except hair dryers and high-power cooking. The 1600VA covers nearly everything short of a full-power induction hob.

The Phoenix has a VE.Direct port for monitoring via Cerbo GX or a standalone display. Its remote on/off function lets you control it from a panel-mounted switch away from the inverter.

Victron MultiPlus (Inverter-Charger Combination)

The MultiPlus combines a pure sine wave inverter with a mains charger in a single unit. It also includes an automatic transfer switch — when you plug into shore power, it instantly (typically within 20ms) switches from inverting to passing through mains power and simultaneously starts charging the battery. When shore power is removed, it instantly switches back to inverting.

This makes shore power integration seamless — appliances don't notice the transition.

The MultiPlus is more expensive than a separate inverter + mains charger, but the integration and automatic transfer switching are genuinely valuable for full-time van life. The 50A mains charger output on the 1200/50 charges a 200Ah LiFePO4 from 20% in about 4 hours.

For builds with a Cerbo GX, the MultiPlus integrates directly — it can be remotely controlled, its settings adjusted, and its status monitored from the VRM app.

Budget Pure Sine Wave Alternatives

These work well as standalone inverters without Victron ecosystem integration. Suitable for budget builds or builds where you don't need remote monitoring.

Installation and Wiring

Inverter installation is the most safety-critical part of a campervan electrical build. The DC-side cables carry enormous currents; the AC-side produces lethal voltages.

Cable Sizing for the DC Side

Inverter cables carry the highest currents in the entire system. Undersizing them is a fire risk.

Cable sizing table (for 12V systems):

These are minimum sizes. Cable slightly larger than calculated is acceptable; smaller is not.

Use flexible, fine-stranded cable (Class 5 or 6) with tinned copper conductors. Stiffer multi-strand cable is acceptable for short, straight runs but flexible cable is easier to route in a van.

See how to install an inverter in a campervan for the complete step-by-step guide.

Fusing the DC Side

A dedicated ANL fuse must be placed in the positive cable between the bus bar (or battery) and the inverter, within 300mm of the bus bar connection.

Fuse sizing:

Inverter Placement

Keep DC cables short. This is the most important placement rule. Every metre of 35mm² cable at 100A adds approximately 0.057V of voltage drop per metre (each way). A 1m run on each side (2m total) causes 0.11V drop — less than 1%. A 3m run on each side causes 0.34V per side = 0.68V total — approaching 6% at the inverter. At full load, 6% voltage drop means the inverter's low-voltage alarm may trigger even with a healthy battery.

Mount in a ventilated space. Inverters get warm under load — some get quite hot at high loads. They need airflow around them. Don't mount inside a fully sealed cabinet without ventilation gaps at top and bottom. The Victron Phoenix has a fan that activates at a temperature threshold; ensure the fan isn't obstructed.

Remote switch cable: Most inverters have a remote on/off terminal (two small terminals on the control panel). A small switch wire runs from these to a panel-mounted switch. This means you can switch the inverter on and off from your living area without going to where the inverter is physically mounted.

Accessibility: You should be able to reach the inverter to observe its status lights and check the ANL fuse. Mounting it deep in an inaccessible void behind fixed furniture is poor practice.

AC Side Safety: RCD and Consumer Unit

This is where the 230V electrical safety requirements apply.

The RCD:

All 230V circuits powered by the inverter must be protected by a 30mA Type A (or Type F) RCD. The RCD is placed between the inverter's AC output and the 230V sockets/consumer unit.

A double-pole RCD disconnects both the live and neutral simultaneously. This is the correct type for mobile installations.

Consumer unit:

For more than one or two 230V circuits, install a small consumer unit between the RCD and your sockets. The consumer unit contains MCBs (Miniature Circuit Breakers) — one per circuit. MCBs protect the 230V wiring, not just the RCD. A typical van consumer unit might have:

• 1× 20A MCB for the mains charger circuit
• 1× 16A MCB for ring socket circuit
• 1× 16A MCB for dedicated appliance (e.g., induction hob)

Neutral-earth bond:

In a standalone inverter installation, the inverter's AC output neutral must be bonded to earth (vehicle chassis) at the inverter. This ensures that if a live wire contacts the chassis, the RCD will detect the fault current and trip.

Check your inverter's manual — some inverters include this bond internally; others require an external neutral-earth link.

Warning: If you have both a standalone inverter and a shore power inlet wired to the same RCD/consumer unit, you need a changeover arrangement — either an automatic transfer switch (built into a MultiPlus) or a manual changeover switch — to ensure only one source is connected to the consumer unit at a time. Connecting shore power live to an active inverter output would be dangerous.

See inverter transfer switch for a campervan for options.

230V Socket Wiring

From the consumer unit to sockets, use 2.5mm² three-core flex (brown/live, blue/neutral, green-yellow/earth). Maximum socket circuit current for 2.5mm² cable in a van is 20A (4,600W at 230V) — well above what any campervan load would actually demand.

Socket placement considerations:

• Keep sockets away from the kitchen sink/splash zone
• Don't place sockets where they'll be trampled or subject to regular impact
• Use flush-mounting van sockets (not standard household back boxes, which are too deep for thin panels)

Running Specific Appliances: What to Expect

Laptop Computers

First, check: does your laptop charge via USB-C? If yes, skip the inverter for the laptop — use a 12V USB-C GaN charger instead.

If your laptop needs a 230V adaptor (older models, some gaming laptops, MacBook Pro before USB-C era): the inverter load is small — 45–90W typically. A 300W inverter handles this easily.

Battery drain from laptop via inverter: 65W × (1 ÷ 0.90 efficiency) = 72W from the battery = 6A from a 12V battery. For 8 hours of use: 48Ah from the battery. A 200Ah LiFePO4 handles this without issue.

See low-frequency vs high-frequency inverter for a campervan for why this distinction matters for powering laptops and sensitive electronics.

Coffee Machines

Nespresso / Dolce Gusto pod machines: Typically 1,100–1,400W. These are the most popular coffee inverter load. A 1,600W inverter handles them comfortably. The machine is on for 30–60 seconds per cup.

Energy per cup: 1,200W × (45 seconds ÷ 3,600 seconds per hour) = 15Wh. At 12V with 90% efficiency: 1.4Ah per cup. Entirely manageable.

Espresso machines (pump type, e.g., Breville Bambino): 1,200–1,450W during heating; 900W during pump operation. Need a 1,600W+ inverter to handle the heating element.

12V alternatives: The Outin Nano (12V, £70) makes genuine espresso with a 12V DC input — no inverter needed. For someone who just wants their espresso fix, this is far more efficient than running a 1,200W machine through an inverter.

See coffee machine in a campervan: inverter or 12V? for a complete comparison.

Hair Dryers and Hair Styling Tools

Standard hair dryers: 1,200–2,200W. High-end Dyson Supersonic: 1,600W. A 1,200W hair dryer needs a 1,600W inverter; a 2,000W dryer needs a 2,400W inverter.

Hair straighteners: 200–250W. A 500W inverter handles these easily.

Battery impact of a hair dryer: 1,200W × (10 minutes ÷ 60 min) ÷ 0.90 efficiency ÷ 12V = ~19Ah from the battery for a 10-minute blow-dry. Manageable daily for someone with a 200Ah battery.

Induction Hobs

Induction hobs are the most power-hungry inverter load that people regularly want to run in a van. A single-burner induction hob at maximum power draws 1,800–2,000W. A two-burner hob at full power exceeds 3,000W.

Practical reality for battery power:

At 1,800W through a 2,000W inverter, a 200Ah LiFePO4 battery is depleted in approximately: 200Ah × 0.80 usable × 12V ÷ (1,800 ÷ 0.90) = 96 minutes of cooking

That's 96 minutes of actual induction cooking before the battery reaches 20% SoC. For someone who cooks a 20-minute meal once a day, a 200Ah battery works. For someone who wants to bake bread and cook three courses, 400Ah or shore power is needed.

A practical approach: use the induction hob for quick cooking (boiling water: 3–5 minutes; stir fry: 8–10 minutes) and a small gas hob for longer simmering. This drastically reduces battery consumption.

See what can a 2,000W inverter run in a campervan? for a complete analysis.

Power Tools

Drills, jigsaws, sanders, and grinders can be run from an inverter. The key issue is the surge current at motor startup.

A 900W angle grinder has a startup surge of 2,500–3,000W. A 1,000W continuous / 2,000W peak inverter cannot handle this — it will shut down during startup. Either use a 2,000W continuous / 4,000W peak inverter, or consider a cordless tool instead.

For occasional DIY use during a van build, many builders run power tools off a generator rather than inverter. The generator handles the surge more robustly.

See running power tools with a campervan inverter for the full guide.

Inverter Standby Draw

A switched-on inverter draws power even when no load is connected. This idle/standby current varies by model:

Over 24 hours, a 10W standby draw consumes 240Wh — about 20Ah from a 12V battery. This is significant over a week: 1,680Wh or ~140Ah wasted. Switch the inverter off when you're not using it. This is why a remote on/off switch is valuable — you can switch the inverter off from bed without going to where it's mounted.

The Victron Phoenix has a "power save mode" that reduces standby draw by monitoring for an AC load and waking up when one is detected. The response time is ~20ms — appliances notice a brief delay, but phones and laptops don't care.

Earthing the Inverter

All exposed metal parts of the inverter must be earthed to the vehicle chassis. This is both a safety requirement and ensures the RCD works correctly.

Most inverters have a dedicated earth terminal. Connect this to the vehicle chassis with a short, adequately rated earth cable (minimum 4mm² for small inverters, 10mm² for large ones).

The DC negative input to the inverter is connected to the negative bus bar, which in turn is connected to the chassis via the chassis earth bond. But the AC earth terminal should have its own dedicated chassis connection — don't rely on the shared DC negative path for AC earthing.

Troubleshooting Inverters

Inverter shuts down immediately under load:

1. Check battery voltage under load — if voltage sags below the inverter's low-voltage cutoff (typically 10.5V for a 12V inverter), the inverter shuts down. This indicates either a discharged battery, a battery with insufficient C-rate capability, or undersized cables causing voltage drop.

2. Check the load's startup surge — a motor appliance may be demanding more surge current than the inverter's peak rating. Use a lower-wattage appliance first to confirm the inverter itself is functional.

Inverter producing noise through audio equipment:

This indicates an earth loop or the inverter's output waveform is contaminating the audio ground. Try adding a mains filter between inverter output and audio equipment. Check that the inverter earth terminal is connected to chassis.

RCD trips when inverter turns on:

The RCD is detecting a leakage current from the inverter's internal components to earth. Some inverters have relatively high natural leakage through their EMI filters — this can trip a very sensitive RCD. Try a different RCD (some are rated for use with variable-frequency drives and inverters) or check the inverter's neutral-earth bond configuration.

Inverter alarm but no apparent fault:

Check the temperature — many inverters alarm at high temperature before shutting down. Improve ventilation. Also check the battery voltage — a low-battery alarm sounds before the low-voltage shutdown.

Related Guides

• Campervan electrical system guide — the complete overview
• Campervan battery guide — sizing the battery bank that powers your inverter
• Campervan charging systems guide — keeping your batteries charged
• Campervan wiring & safety guide — cable sizing and fusing for inverter circuits
• Campervan solar setup guide — generating the power your inverter converts

FAQ

What size inverter do I need for a campervan?

For light use (laptop, small devices): 500W. For a coffee machine: 1,500W. For a hair dryer: 2,000W. For an induction hob: 2,000W+. Most van lifers settle on a 1,000–1,600W pure sine wave inverter as a practical all-rounder that handles everything except the largest loads.

Pure sine wave or modified sine wave?

Always pure sine wave. Modified sine wave can damage laptops, CPAP machines, motor-driven appliances, and anything with a microprocessor. The extra £50–£100 for pure sine wave is worth it every time.

Can I run a kettle on a campervan inverter?

A standard kettle draws 2,500–3,000W — you'd need a very large inverter and a large battery bank. For practical daily use, use a 12V kettle (draws ~100–150W) or heat water with a gas stove. Save the inverter for appliances that don't have good 12V alternatives.

Does an inverter drain the battery when not in use?

Yes — typically 5–20W on standby. Switch the inverter off at the remote switch when not in use. A 10W standby draw over 8 hours of "not using it" wastes 80Wh — meaningful across a week.

Can I run an inverter and shore power at the same time?

Only if they're properly switched to prevent them connecting to each other simultaneously. A Victron MultiPlus handles this automatically. With separate units, you need a manual or automatic transfer switch. Never connect shore power to an active inverter output.

How long can I run an inverter on a 200Ah LiFePO4 battery?

At 100W load: approximately 16 hours. At 500W: approximately 3 hours. At 1,000W: approximately 1.7 hours. At 2,000W: approximately 50 minutes. These assume 80% usable capacity and 90% inverter efficiency.

Is a 12V inverter better than a 24V inverter for a campervan?

For most campervans (12V battery system), a 12V inverter. The 24V inverter only makes sense if you have a 24V battery bank. The inverter's output voltage (230V AC) is the same regardless — the input voltage (12V or 24V) is what changes.