What size generator do I need to run an RV air conditioner?
A 13,500 BTU rooftop unit runs at about 1,300 to 1,600 watts but surges to roughly 2,800 to 3,000 watts on startup, so it needs the 3,000 to 3,500 watt class of generator. A 15,000 BTU unit surges higher, around 3,300 to 4,000 watts, and needs more, or a soft-start device, or load management. The startup surge, not the running draw, is the bottleneck. That is why a small 2,000 watt generator that looks big enough on paper trips out the moment the compressor kicks on. The calculator above sizes on the surge for exactly this reason.
What is the difference between running watts and starting watts?
Running watts are the steady power a device uses to keep operating. Starting watts are the brief, much higher burst a motor or compressor pulls for a fraction of a second to get spinning, often two to three times the running figure. Heaters, kettles, toasters, TVs, and laptops have no real surge, so their starting watts equal their running watts. Air conditioners, fridges, pumps, and power tools do surge. Size your generator so its running rating covers your total steady load and its starting rating covers your single biggest surge.
Can a 2,000 watt generator run an RV air conditioner?
Usually not on its own. A typical 2,000 to 2,200 watt inverter generator (like a Honda EU2200i) tops out around 2,200 surge watts, and a 13,500 or 15,000 BTU air conditioner's startup surge exceeds that, so the generator trips its overload protection and cuts out. The fix is a soft-start device (such as a Micro-Air EasyStart or SoftStartRV), which cuts the air conditioner's startup surge by roughly 65 to 70 percent. With one fitted, a 2,000 to 2,200 watt inverter can reliably run a single 13,500 BTU unit, as long as other big loads are not starting at the same moment.
What size generator for a 30-amp vs a 50-amp RV?
A 30-amp RV can draw at most 3,600 watts (120 volts times 30 amps), so a 3,000 to 3,500 watt inverter generator runs it comfortably, one air conditioner included. A 50-amp RV is a different animal: it has two 120-volt legs for up to 12,000 watts and often two air conditioners, so you generally need a 7,500 watt or larger generator, or you manage the load by not running everything at once. The calculator's recommendation follows whatever you actually tick, so it lands in the right class for your real setup rather than your rig's wiring rating.
What size generator do I need for a refrigerator?
A typical refrigerator runs at about 400 to 800 watts but surges to roughly 1,200 to 1,600 watts when the compressor starts, so any inverter generator of about 2,000 watts or more covers a fridge with room to spare. The surge is brief, but it is real, which is why a fridge counts as a surge load in the calculator while a TV or laptop does not. If the fridge is the only motor in your list, it becomes the single largest surge the tool adds to your running total.
Is it safe to run a generator while sleeping?
No. A gas generator's exhaust is carbon monoxide, an odorless, colorless gas that can build to fatal levels within minutes, and people who are asleep cannot recognize the symptoms in time. Never run a generator indoors, in a garage, in an enclosed or partly enclosed space, in a van you sleep in, or within 20 feet of any door, window, or vent, even with things open. Run it outside, well away, with the exhaust pointed away from you, and use battery-powered carbon monoxide alarms. For powering an enclosed space you sleep in, a battery power station is the safe answer, because it has no engine and produces no carbon monoxide.
Inverter generator or conventional generator?
For an RV, van, or boat, choose an inverter generator. It produces clean, stable power (under about 3 percent total harmonic distortion) that is safe for laptops, phones, and sensitive electronics, it is much quieter, it sips less fuel at light loads because the engine throttles to match the demand, and many models pair in parallel for more power. Conventional open-frame generators are cheaper per watt but louder, thirstier, and put out dirtier power that can be hard on electronics. The extra cost of an inverter is usually worth it for the way most of us actually use one.
Can I run my whole RV on one generator?
A 30-amp rig, yes: a 3,000 to 3,500 watt inverter generator runs one air conditioner plus the basics. A 50-amp rig with two air conditioners is harder, and you either step up to a 7,500 watt or larger unit or you manage the load, running one air conditioner at a time and not firing the microwave while something big is starting. Soft-start devices on the air conditioners help by shrinking the surges. Size it with the calculator for the loads you genuinely run together, not for the rig's full wiring capacity, which you rarely use all at once.