An inverter converts your 12V DC battery power into 120V AC power - the same power that comes out of wall outlets in your house. This lets you use normal laptops, phone chargers, kitchen appliances, and pretty much anything else you'd plug into the wall.
If you're building a van with any kind of electrical system, you need an inverter. The question is: what size, and which brand?
Match your inverter to your battery's BMS: 2000W if you have one 280Ah pack (200A BMS), 3000W if you have two in parallel (~400A combined). The pure sine wave Vevor in either size lands around $150-200 — pick the one your battery bank can actually feed.
Let me explain why size, not just brand, depends on the battery side.
Inverters are rated by their continuous output (what they can deliver constantly) and their surge/peak rating (what they can handle for a few seconds when something starts up). Both numbers matter — but neither matters until you check the third number that gates them: how much current your battery's BMS will actually let through.
Every LiFePO4 pack has a BMS continuous-current rating. If the inverter pulls more than that, the BMS protects the battery by disconnecting it — your AC loads drop, and so does everything else on the 12V side. So the ceiling on the inverter you can run isn't the inverter spec, it's:
max inverter watts ≤ BMS continuous A × 12V ÷ 1.25
The 1.25× margin covers inverter inefficiency (~85-90%) plus headroom so the BMS isn't running pinned to its limit. Skip the margin and you'll get nuisance trips every time a compressor and an induction burner ramp at the same time.
The surge rating matters because many devices draw much more power for a second or two when they start up. A blender might run at 800W but needs 1500W to start. An induction cooktop might run at 1200W but surge to 2000W when you first turn it on.
A 3000W inverter typically has a 6000W surge rating, which means it can handle pretty much anything you throw at it.
Here's the thing that surprises people: the price difference between inverter sizes is minimal.
On Vevor that's $50 to go from 2000W to 3000W. On other budget brands it's $100-150. Either way the price difference is a rounding error — as long as your battery bank can actually feed the bigger inverter (see the BMS-ceiling rule above).
But the capability difference is huge:
The 3000W inverter gives you flexibility. You're not constantly doing mental math about whether you can turn on the blender while your laptop is charging. You're not limited to cooking on low power. You can run whatever you need without stress.
The kind of system that justifies a 3000W inverter — induction cooktop, hair dryer, Starlink, and a laptop, all running off the same bank. Hover the AC branch to see how peak watts size the inverter cable.
Educational estimates only — not a substitute for a licensed electrician. Verify against ABYC E-11 and manufacturer specs before installing. See full disclaimer.
BETA — Educational estimate, not an engineered design.
Verify all wire gauges, fuse and breaker ratings, run lengths, and system sizing against ABYC E-11, manufacturer spec sheets, and a licensed electrician before installing or energizing. Ampacity uses ABYC E-11 single-conductor, free-air, 105 °C-insulation copper (typical marine BC-5W2); resistance is NEC Ch. 9 Table 8 at 75 °C; system is nominal 12 V DC and 120 V AC. Wire rated below 105 °C, ambient-temperature derating, and bundle derating are not applied. No code-compliance review or engineering sign-off is provided or implied.
Source: morevanlessmoney.com/tools/electrical/diagram · Full terms: morevanlessmoney.com/legal/terms
This is where the extra power really matters. As we discussed in the cooking section, induction cooktops are now the best option for most van builds - no propane to deal with, very efficient, easy to use.
But here's the catch: induction cooktops are power-hungry.
A portable induction cooktop typically runs 1000-1500W when cooking at high heat. Plus they surge even higher when they first turn on - often 1800-2000W for a second or two.
You're right at the limit. It might work on medium power, but high power could overload it. The surge when you first turn it on might trip the inverter. You're babysitting it constantly.
Turn it on, cook at whatever power level you want, don't think about it. Boil water fast. Sear that steak. It just works.
Same thing with blenders, electric kettles, etc. These are convenience items that make van life way better, but they need real power. A 3000W inverter means you can actually use them.
The most common "my inverter keeps tripping" forum post has nothing to do with total wattage. It's about inrush current — the brief, massive spike that motors pull when they start. If you plan to run a compressor-based fridge, a rooftop air conditioner, or any pump, read this before you pick an inverter.
A resistive load (electric kettle, induction cooktop, space heater element) draws exactly what the label says. Turn it on, it pulls 1500W, done. Predictable.
A motor-driven load — anything with a compressor or pump — is different. At the instant of startup, before the rotor is spinning, the motor is effectively a short circuit. For 100-500 milliseconds it can pull 3-7× its running current, then settles. AC nameplates spell this out as LRA (locked rotor amps) versus RLA (rated load amps). Ratios of 4:1 or 5:1 are normal.
2-7A running (varies by model and ambient), ~7-10A inrush. Almost a non-issue on a healthy 12V system.
12-16A running @ 120V (~1400-1600W), LRA ~55-65A = 6600-7800W momentary surge. This is the appliance that breaks inverters.
300-700W running. Variable-speed compressor ramps up from zero — essentially no inrush.
1200-1800W continuous, small inrush (a brief burst as the input capacitors charge, not motor LRA). Modern units use active power-factor correction and present a near-unity, near-resistive load to the inverter.
A "3000W continuous / 6000W peak" inverter can hold 3000W forever and ride out 6000W for a brief window — typically 100ms to 2 seconds. If an appliance's inrush exceeds the peak rating, the inverter faults out. Worse, your battery's BMS may trip first: LiFePO4 BMS units often have a continuous current limit around 200A with a short peak allowance, and a 500A+ draw from the inverter during compressor start can hit that ceiling before the inverter even notices. See the BMS surge limits discussion in the batteries guide.
Trust but verify: cheap no-name inverters routinely overstate peak ratings. A $120 "3000W/6000W" unit often cannot actually hold 6000W for even 100ms. Stick with brands that have a track record (Vevor, Giandel, Renogy, Victron) or bench-test before you bet a rooftop AC on the spec.
A Micro-Air EasyStart 364 or SoftStartRV module wires into the compressor and ramps it up over about a second instead of slamming it on. Reduces inrush by 65-75% — module itself runs ~$380, plus a wiring kit or your own labor. This is what makes a 13,500 BTU rooftop AC run on a 2000-3000W inverter instead of requiring a generator.
DC mini-splits (Mabru, Nomadic, Velit) and Danfoss BD-series fridge compressors use inverter drives that start at minimum RPM. No inrush, no soft-start, no problem. If you're still shopping for AC, this is the easy answer — more detail in the air-conditioning guide.
Another reason 3000W is the sweet spot: the extra headroom absorbs motor startups without drama. Going from 2000W to 3000W typically buys you another ~4000W of peak capacity. On a Vevor 3000W (~$200) that headroom is essentially free — cheaper than buying a soft-start, and usually cheaper than oversizing the battery bank too.
A ~$20 cap that briefly boosts starting torque. Helps a little, but a modern soft-start module does the job properly and gives you data. Skip the cap, buy the EasyStart.
A 13,500 BTU Dometic rooftop with a stock compressor draws ~60A LRA = roughly 7200W for a fraction of a second. On a 3000W / 6000W-peak Vevor inverter it will usually trip on first startup — the surge exceeds peak and the inverter protects itself. Even if the inverter rides it out, the BMS often won't.
Add a Micro-Air EasyStart 364 (~$380) and inrush drops about 70% — down to ~18-20A, roughly 2200W. The same AC now starts cleanly on a 2000W inverter, and running load settles at ~1400W, well inside continuous.
That's the entire game: a few hundred dollars of soft-start buys you thousands in battery and inverter capacity you no longer have to install.
This is non-negotiable: you need a pure sine wave inverter.
Modified sine wave inverters are cheaper but they:
Pure sine wave inverters produce clean power identical to what comes out of your wall at home. Everything runs properly, efficiently, and safely.
Every inverter recommendation in this guide assumes pure sine wave. Don't even look at modified sine wave inverters - they're not worth it.
This is another area where conventional wisdom is stuck in the past. Five years ago, you really did need to spend $800-1200 on a Victron or Magnum inverter to get something reliable. The cheap Chinese inverters were genuinely problematic.
That's changed. Budget brands like Vevor, Giandel, and others are now making inverters that work just fine for van builds, at a fraction of the cost of the premium brands.
(Victron, Magnum, Samlex)
(Vevor, Giandel, etc.)
The Vevor inverters offer comparable quality to Renogy (which is already a mid-tier brand, not premium), at a much lower cost.
Are they as good as a $1200 Victron? No. Will they work fine for most van builds? Yes.
Here's the thing: even if your Vevor inverter dies after 5 years, you can buy three of them for the cost of one Victron. And in 5-10 years, the technology will probably be even better and cheaper, so maybe you'll upgrade anyway.
For a DIY van build where you're trying to keep costs reasonable, spending ~$200 on a 3000W Vevor inverter makes way more sense than spending $1200 on a 3000W Victron.
Running an inverter does use some power, but it's not as bad as people think.
This is called parasitic draw. Over 24 hours, a 3000W inverter sitting idle uses about 360-720 Wh per day just being on.
That's not nothing, but it's also not terrible if you're running a fridge (400-600 Wh/day) and other devices anyway. And here's the key: you can turn the inverter off when you're not using it.
Many people wire their inverter with a remote on/off switch that they can reach from inside the van. Inverter off at night (just run 12V devices), inverter on during the day when you need AC power. This cuts the idle draw to almost nothing.
When you run a device through an inverter, you lose about 10-15% of the power to conversion losses. So if your laptop needs 50 watts, the inverter pulls about 55-60 watts from your battery.
This is why we recommend running DC devices (like 12V fridges and diesel heaters) directly off your battery when possible - no inverter losses. But for things that need AC power anyway (laptops, phone chargers, induction cooktop), the 10-15% loss is just the cost of doing business.
Mount your inverter somewhere accessible but out of the way. Common spots:
Keep it close to the battery (short wire runs are more efficient), but not so hidden that you can't reach it.
Inverters generate heat, especially under load. Don't seal them in a completely enclosed box. They need some airflow.
Some people mount computer fans to actively cool their inverter compartment. This is optional but can help if you're running high loads frequently.
A 3000W inverter pulls ~250-280A continuous from a 12V bank (3000W ÷ 12V ÷ 90% efficiency) and surges higher when motors kick on. The canonical feeder is 4/0 AWG — rated around 300A continuous in cabin temperatures with margin for surge. A 2000W setup at ~185A continuous runs fine on 2/0 AWG. Specifics in the wiring and connections guide.
Short runs are critical. Keep the inverter within 3-4 feet of the battery if possible. The longer the run, the thicker the wire needs to be.
A 3000W inverter feeder needs a 300A class-T fuse within 7 inches of battery positive (200A class-T for a 2000W setup). Not ANL, not MEGA, not a DC breaker on a lithium main. A healthy LiFePO4 bank can dump 5,000A+ into a dead short, and class-T is the only common DC fuse with the AIC (fault-clearing capacity) to actually interrupt a fault that big — full reasoning on the fuses and breakers page.
This is not optional. An unfused 4/0 cable in a short circuit will weld metal and start fires. An ANL fuse on a lithium main can fail to clear the fault and ends up the same way — class-T or nothing on the battery side.
Many inverters come with or support a remote on/off switch. Wire this somewhere convenient (near your bed, by the door, etc.) so you can turn the inverter on and off without accessing the inverter itself.
This is really handy for managing that idle draw.
When shopping for an inverter, look for:
Keep it simple. You need an inverter that converts 12V to 120V safely and reliably. Everything else is gravy.
Some inverters are combined with battery chargers - these are called inverter/chargers or multiplus units (Victron makes a popular one).
One unit that can both invert DC to AC, and also charge your batteries from shore power or a generator. When you plug into shore power, it charges your batteries and also passes through power to your outlets. When unplugged, it inverts from battery.
Skip the inverter/charger and keep it simple. Get a separate 3000W inverter (~$200 from Vevor) and if you want shore power charging capability, add a separate battery charger ($150).
Total cost: ~$350 vs. $2000+ for an inverter/charger.
You can always add shore power charging later if you decide you want it.
To give you a sense of what 3000W actually means in practice:
This is the flexibility you get with 3000W - you don't have to think about it. You can run multiple things without doing mental math.
There is one scenario where a smaller inverter might make sense: if you're building an absolutely minimal system.
Maybe you're doing a bare-bones weekend warrior build with:
In this case, a 1000W inverter ($150) might be fine. You're not running an induction cooktop, you're not running a blender, you're just keeping devices charged.
But honestly? Even then, I'd probably still get the 2000W or 3000W inverter for $100-200 more. Because in six months you might want to add a blender. Or in a year you might want to try induction cooking. And then you'll wish you had more inverter capacity.
The cost difference is so small that you might as well get the 3000W and have the flexibility.
Get a 3000W pure sine Vevor (~$200) if your battery bank can feed it — two 280Ah packs in parallel, or a single Battle Born GC3 270Ah with a 300A BMS. On a single Eco-Worthy 280Ah (200A BMS), the right pairing is the 2000W Vevor (~$150) — pushing a 3000W on a 200A BMS trips the battery before the inverter notices.
Skip the premium brands unless you're building a professional commercial van. The Vevor/Giandel/etc inverters deliver comparable quality at a fraction of the price.
And definitely get 3000W instead of 2000W. The small price difference opens up way more possibilities in your van. You'll never regret having too much inverter capacity, but you'll definitely regret having too little when you want to cook something fast and your inverter can't keep up.
At ~$200 from Vevor, a 3000W inverter is barely more than a 2000W - but it gives you a lot more capability and flexibility. It's worth it.