Power Primer: RV Generator FAQ

Whether you’re boondocking in the desert or riding out a power outage at a campground, generators are integral to RV life. This overview walks through built‑in vs. portable units, fuel options, safety, noise and campground etiquette and the big differences between types and models.

Built‑in vs. Portable

Many motorhomes and some higher‑end fifth wheels come with a built‑in generator mounted in a dedicated compartment and wired into the RV’s electrical system. These units typically share the RV’s main fuel tank (gas or diesel) or a permanently mounted propane tank, so you don’t have to haul separate cans. They’re started from a switch inside the coach, can be used while driving to run the air conditioner, and are sized to power most or all onboard systems, including large AC units. Because they’re hard‑mounted and vented by the manufacturer, they’re convenient and safe when properly maintained.

Portable generators sit outside the RV and connect through the shore‑power cord or a transfer switch. They’re popular with travel trailers, camper vans without factory gensets, and anyone who wants more flexibility or a backup to a built‑in unit. Portables typically range from small 600–2,000-watt units that mainly recharge batteries and run small loads, up through 3,000–4,500-watt models that can handle a single RV air conditioner plus other basics. Some folks carry larger generators in the bed of their truck to power two air conditioners and everything else. The trade-offs on portables: You must store them, lift them up and down, refuel them by hand, run power cords and position them so exhaust and noise don’t bother you or your neighbors.

In practical use, built‑ins win on convenience and high continuous output, while portables win on versatility and initial cost. For example, a van owner might use a 2,500‑watt portable to keep batteries and a small AC running when off‑grid, then carry the same unit for home backup when not traveling.

Power cords must be sufficiently rated to carry the expected load. The longer the run, the more power loss occurs. To reduce losses, heavier gauge wires are needed. Make sure your generator has the correct power outlet for the power cord.

Fuel Types

Most RV generators run on one of three fuels: gasoline, diesel or propane. Gasoline units are common in gas motorhomes and as portable inverter generators. They’re easy to refuel produce good power density, and usually cost less up front. But gas goes stale more quickly in storage than other fuels and is more volatile to handle. Be sure to drain the fuel, including the carburetor, before storage.

Diesel generators pair naturally with diesel motorhomes and offer better fuel efficiency and longer engine life, but the units themselves are heavier and more expensive than other options, and portable diesel models are relatively rare.

Propane generators can be either built‑in (tied to a large ASME tank) or portable dual‑fuel units that can switch between gas and propane. Propane burns cleaner and stores indefinitely without going bad, which is attractive for occasional use. The downside is reduced power output and shorter runtime for the same tank size compared with gasoline or diesel,—in other words, you may burn through your onboard propane faster, especially if you also use it for heating and cooking. 

Dual-fuel portable generators have become popular. Just keep in mind that they have lower output ratings when running on propane.

In recent years, some RVers have begun using battery‑based “solar generators” or portable power stations instead of, or alongside, traditional fuel‑burning generators. These run silently and emit no exhaust, making them ideal for light loads and strict quiet‑hour areas. But they are limited by battery capacity and must be recharged via shore power, vehicle alternator, wind or solar. Many people end up with a hybrid system: solar plus batteries for everyday loads and quiet hours, and an engine‑driven generator for heavy or extended demand like running air conditioning.

Noise decibels & quiet hours

Noise is often the biggest generator complaint in campgrounds. Generator sound is measured in decibels (dB), typically at a distance of 20–23 feet. Quiet inverter generators usually advertise ratings in the 50–60 dB range at a quarter‑load, which sounds like a normal conversation or a busy restaurant. Contractor‑style open‑frame generators can easily run in the 70–80 dB range or higher, which is more like a lawnmower—very noticeable at a quiet campsite.

Most public campgrounds publish quiet hours, often around 10 pm to 6–7 am, when generators cannot be used at all. Some national parks and public lands also limit run times during the day, for example allowing generators only in set windows (like 8–10 a.m. and 4–6 p.m.) and may specify a maximum dB rating at a set distance. 

Even where rules are loose, good etiquette is to run the generator only as long as needed, position it as far from neighboring sites as your cord allows, and point the exhaust away from people.

Because heat and air conditioning require huge power loads, planning around quiet hours matters. Many RVers cool the rig heavily before quiet hours, then rely on battery power and fans overnight. Others upgrade their battery and inverter systems so they can avoid nighttime generator use entirely. A smaller, quieter unit, run longer at lower load, is often more campsite‑friendly than a big, loud unit roaring at high output for short bursts.

Inverter vs. contractor‑style generators

The most important technical choice is between an inverter generator and a conventional contractor‑style generator. Inverter generators produce AC power in a different way: they create DC power, then use electronics to invert it into clean, stable AC with a pure sine wave and tightly controlled voltage and frequency. That makes them safe for sensitive electronics like laptops, CPAP machines, LED TVs and modern RV control boards, which can be damaged or glitchy on “dirty” power. Because the engine can throttle up and down to match the load, inverter models are significantly more fuel‑efficient at partial loads and much quieter.

Contractor‑style generators, often seen on construction sites, use a fixed‑speed engine directly tied to an alternator to produce AC. They’re cheaper per watt and can provide large amounts of power, which is why many budget‑minded RVers are tempted by them. However, they tend to be much louder, heavier, and less fuel‑efficient at lighter loads, and their power often has higher harmonic distortion. That can be hard on small electronics and can create flicker or noise in sensitive devices. For off‑grid RV use, especially around other campers, this noise difference is dramatic.

For most RVers, a modern inverter generator in the 2,000–3,500 watt range hits the sweet spot: enough power to run battery chargers, a microwave and sometimes a single air conditioner, with low noise and good fuel economy. Larger rigs that need to run two air conditioners or big loads at once sometimes use multiple inverter generators in parallel or a built‑in generator designed specifically for RV use. Contractor‑style generators are best reserved for situations where noise is less of an issue and initial cost per watt is the top concern, such as running tools away from camp or as an emergency backup at home rather than at a crowded campground.

Lifestyle & Power Usage

Choosing the right generator starts with listing your likely loads. Air conditioners, microwaves, battery chargers, residential refrigerators and medical devices each draw significant power. A couple who mostly boondocks in moderate weather might get by with a 2,000‑watt inverter generator that runs a charger, laptops and a coffee maker, backed up by solar for daytime charging. A family in a large trailer in a hot climate, such as an Arizona summer, may need at least 3,000–3,500 watts of power to run an air conditioner comfortably. If you need to run two air conditioners, you’ll need even more wattage. Some inverter-type generators can be paired together with a special wiring harness that matches their frequency and makes them act as if they were one unit. Look for that feature when shopping for portable generators.

Beyond wattage, think about how you camp. If you move frequently and camp in public parks with strict quiet hours, prioritize low‑decibel inverter models and good battery capacity, even if that costs more. If you usually plug into full‑hookup sites and only occasionally need backup power, a mid‑size portable or factory built‑in unit used sparingly may be sufficient. Whatever you choose, follow campground rules, mind your neighbors, and position and maintain your generator properly so it stays a helpful tool instead of a source of conflict.

A reliable starting point is to use a generator manufacturer’s online sizing calculator, then cross-check it with a simple manual wattage calculation. Be aware that generators typically have two ratings, peak and continuous. Only use the continuous rating, and leave some surplus capacity (at least 20-25%) in reserve. When electric motors such as in air conditioners start, they briefly draw 200-300% more “peak” power. Adding a Soft-Start kit to your air conditioners can also significantly reduce required starting current.

Generators lose power at higher temperatures and elevations where the air is thinner. A good rule of thumb is 3% loss per 1,000 feet elevation gain. So at 10,000 feet expect about a 30% power loss.

Service & Safety

Generators need regular service based on operating conditions and run time in hours. This includes oil, air and fuel filter changes, spark plugs and other items according to manufacturer recommendations. Generators produce carbon monoxide (CO) while running, especially at higher elevations, where they run richer. Be sure exhaust is directed away from any RVs and people. You should also have a working CO detector in the coach. 

Never operate a generator in dry grass, brush or any other combustibles. Generators should have a US Forest Service-approved spark arrestor meeting specification 5100-1.

Allow a portable generator to cool down before refueling. Keep a dry chemical fire extinguisher of at least 2.5 pounds rated ABC nearby.