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What Size Generator Do I Need For My RV?

by Don

How to Determine What Size Generator You Need for Your RV

How to Determine What Size Generator You Need for Your RV

Pictured Above: Honda Super Quiet Gasoline Portable Generator with Inverter (EU3000IS1A 3000Watt Electric Start Inverter

How big a generator would I need to run a 110v Refrigerator, TV, VCR and an Air Conditioner in my motor home? I can buy this: Craftsman generator 2400-watt, like new, $200. Would this be big enough?



ANSWER: Hi Don, I am not the bearer of good news, based on what you are going to be powering in your RV, I do not believe that a 2,400 Watt generator is going to be sufficient for your needs.

Let's start by evaluating the wattage usage of the appliances you are planning to use.

Refrigerator A standard Absorption Cycle RV fridge, depending on size, uses anywhere between 400 to 1000 watts of electricity. The majority of RV refrigerators use heat to cause a chemical reaction to cool down the fridge. The heat is either provided by Propane or a 110-volt electrical heating element.

The way you phrased your question made it sound like you are possibly using a home style refrigerator in your RV. A home fridge uses a 110-volt compressor to create the cold. When you use a refrigerator with a compressor, you not only have to worry about how many Watts it uses when running, but it takes 2 to 3 times the wattage to start the compressor every time the fridge cycles the compressor on and off. A small Home type Fridge can use anywhere from 400 to 1000 watts. A larger fridge/freezer combination can use 1000 to 2400 watts.

  New And Used Portable Generators From eBay.com

Air Conditioner An air conditioner uses a compressor to create the cold, so it will also use 2 to 3 times more wattage as the compressor cycles on and off. You can expect an A/C unit to use anywhere between 1,400 to 2,400 watts.

Other Items TV depending on size 200 - 600 watts. VCR 150 - 200 watts. Here are some other items that you may want to use when camping; Microwave 1,000 watts, Coffee Maker 900 watts, Toaster 1,150 watts and Hair Dryer 1,000 watts.

Just using the minimum wattage for the 4 items you mentioned, the total wattage comes out to 2,150 watts, and that is not including the start-up wattage of the compressor on the A/C. It is also assuming that you have an absorption-type RV Fridge. If you use the Microwave or Coffee Maker or Toaster or Hair Dryer while using your other electrical items, you will exceed the generator's 2400 Watt Rating.

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The bare minimum size generator I would suggest you use is a 3,500 Watt generator, and that might even be cutting it close. For just a little over $100.00 more than what you are paying for the used generator you are looking at, you can get a brand new portable generator rated at 3,500 watts or greater. Buying new also has the advantage of having a manufacturer's warranty.

The video below explains how to calculate what size generator you need to run different types of appliances.

New And Used Portable Generators From Amazon.com

I hope that this information has been helpful to you.

Do you have any suggestions or comments on this topic? You can add them to this page by clicking on the "Click Here To Post Comments" link located near the bottom of this page.

Happy RVing

RVing Al

Comments for What Size Generator Do I Need For My RV?

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Excellent advice
by: Jeff J

I think your explanation (and the excellent video) addresses generator purchasing issues quite well. Powering AC was the biggest concern we had when we bought a new trailer - with a single 13,500 BTU roof-mounted AC unit - a few months ago. We envision doing some dry camping/boondocking and wondered if we could do without AC while doing so. Without the need for powering AC, we figured we could get by with a 2000 watt inverter generator. We could always add a second generator and connect them in parallel if we needed more power (for AC). Then we considered that we'd have twice the maintenance concerns and two generators to haul around. We ultimately decided to go with a single 3500-watt generator - which will power everything we have in the trailer - and focused our research based on that specification.

Plz help
by: Tanya

I have a 29ft 05 Jayco trailer and I bought a 4375 watts and it keeps tripping the breaker. So what watts will I need to run my micowave, tv, fridge. And AC.

What size generators needed for 50 amp RV 2 AC units
by: Kim & Mike B

We're 1st time 5th wheel owners and the RV place we bought from wasbt a huge help on the how to's for our home on the road. We need to know what size generators we would need to dry camp with 2 AC units.

We currently have 2 generators Ryobi 2300 starting, 1800 running. They started the ACs but then they got overloaded.

Please any advice would be helpful.

Thank you.
Mike and Kim

Generator size
by: Jake


I have a 1998 38' Fourwinds Windsport. Even though my genset works perfectly fine, I am one that always keeps redundant items. I bought a 3500 watt on wheels portable genset that was actually designed with RV's in mind.. It has both a 30 and 50 amp plug, along with regular 120 vac plugs built into its panel

The cost was about $350 for it.. and it is some generic brand too. Just do a search for 30 or 50 amp portable gensets.

I have run both my AC units at the same time however, I fully recommend you do NOT try to start them at the same time because it is not enough power if both kick in at the same time.. and since staggering them manually like I did is not really something you want to deal with, if you require running both AC units you will want a bigger genset then the 3500 watt unit.

But like, I just run one AC unit normally so it handled that without any problems at all and I was able to plug right into the built 30 and 50 amp sockets for easy use. The unit has about 200 hours on it now in fact and is still going strong.. We use it in places we cannot plug in but don't want to use up fuel or listen to the onboard genset hum all night right under our bed, where it is located.. LOL

Generator for 5th wheel furnace
by: Jet Higbie

Can a generator be used to run a 5th wheel furnace? It is 40,000 btu's, so how many watts would I need? Thank you.

by: Rayneal

Hello I just bought a 27ft aspen trail made by Dutchman, it has one ac-unit, refrigerator/ freezer and a small refrigerator outside,tv/dvd player,what is a recommended size generator for my trailer?

by: Manuel

Hello I just bought a 27ft aspen trail made by Dutchman, it has one ac-unit, refrigerator/ freezer and a small refrigerator outside,tv/dvd player,what is a recommended size generator for my trailer? also looking for the quietest one out there.

by: Anonymous

I have a 17 ft. Travel trailer, I would like to know what size(watts) propane generator would I need? I would like to run : 20"tv, lights, heater, gas 2 burner stove, small refrigerator. No microwave, no ac, no hot water

by: Karl

I was just wondering about the noise level of these generators. Harbor Freight has a "Predator" 4000 max watts (3200 rated watts) what ever that means for a good price but I am not sure if it is enough to run everything or is quiet enough?? Help!

Brute Generator
by: Madime

I'm really not sure how old this thread is, but Malakie, just out of curiosity, are you happy with the Brute? I'm considering one but can't find any reviews on it.

Generator size for RV.. what I did..
by: Malakie


I decided to purchase a backup portable generator because the built in one in our RV is in need of some repairs... which left us without power.

I bought a 'Brute 3250' (made by Briggs & Stratton) for about $350 at Menards. Its standard output is 3250 watts and it can boost up to 5250 watts, it has plugs for standard 120 volt 20 amp x 2 outlets as well as a full 30 amp x 1 plug outlet, which of course my RV power cable plugs right into without any adapter needed. It IS the standard RV plug type outlet.

I am getting about 10-12 hours on a tank of of gas on the unit depending on what is running. To test the capability, (we have a 1998 Four Winds Wind Sport RV) I turned on the fridge, hot water heater, most lights, one of the two roof AC units (could only use one because for some reason we cannot get the second one to turn on, either AC or fan only) and the microwave. It handled the load no problem.

With everything on the generator performed flawless giving me all the power needed without an issue. At that draw though it did suck more gas during that period.

The last few days though we have had the fridge running constant, a few lights here and there as well as a few other accessories plugged in to outlets, and one rooftop AC unit. We have averaged about 11 hours per tank of fuel and had no issues what so ever with power dropping or tripping breakers. Once the internal generator is fixed I will keep this unit as a backup.

Having the built in RV power connector at 30 amps right on the generator IS a very nice feature, to say the least. If you need a second unit or need one period, I can highly recommend it.

BTW, I bought this unit at Menards. I looked at units at Home Depot and Menards and this was the ONLY unit that had the built in RV style 30 amp plug outlet. Even the larger units I looked at did not have that although they did have outlets for 30 amps using standard connectors or 220 volt.

Great information
by: Jim

Great answers to the questions. Your answers are simple and to the point in regards to what it takes to run the different comfort items for the average camper/motorhome. Thanks for your time and effort.

by: Anonymous


Need 120V at 30A
by: Anonymous

Many generators like (Harbor Freight's 69676) that are capable of 220 volts are setup with a center tap neutral and the two hot wires that have 110 v to the neutral or 220V between both hots. They will do say 220v x 15a = 3300w on 220 volt, or TWO 110v Recpt. at 15a = 3300w

For your RV you need 110 Volt at 30 Amp. also 3300 watts, but they are setup with two 110v receptacles with a 13 amp breaker one on each hot wire. So for 110v use you would have to split the load between the two receptacles. with a 50Amp RV you would have to limit the load to 13A. If your AC requires 15A you wouldn't be able to run it at all.

You need one that will do 30amp at 110v. I see that Camping World & Sears had them like that but both reviews are complaining about noise where as the HF one seems to be quite with a big muffler. I see where both brands are rated at 68db

Why tripping
by: CJA

A litte more info is needed. Here are a few things to check.

1) try a new cable (or borrow from neighbor) as a test. A bad or undersized cable will result in high losses and dangerous operations. Partial line to ground fault, loss in the form of heat, voltage, etc.

2) Check the current and voltage under load. A voltage drop is telling as is the current dawn. Check both ends of the power line.

3) Motors draw significantly more current when starting. So, a fridge compressor and AC unit will periodically draw high current. If they kick on at the same time, you can trip. Be sure to measure voltage and current over time and observe average and peaks.

4) generator problems like bad gas, low oil, air filter, fouled plugs or fuel/air mix can cause this type of issue. Does the generator run rough, have smokey exhaust, leave a black residue near the exhaust? Overheating will cause an engine to cut out and will eventually lead to ceasing permanently.

5) Problems in the trailer like the AC unit, etc. Plug a usage meter inline with the cable and generator (on the trailer side). measure the current with different items running, then multiple items. compare readings to nameplate ratings. Be sure to watch over time including average and peak.

If the info above is greek to you, then you need to seek out a knowledgable friend or electrician.

Careful when using Generators.
by: C Catron

As an Electrician with over forty years service. Let me say; be careful when sizing Electric power needs. Talk with your dealer for amount of Wattage needed and type "plug in". Its important not to under size a generator for the load. The unit might even be carried for a good while; but, heat is the by-product. Once you determine the load Wattage needed, then you can decide your needs. Noise is the major factor when RVing, oil gas mixtures don't help and you never know when it might be best to charge your neighbors batteries?

5500KW won't handle 3600KW ??
by: Anonymous

30amp x 120v = 3600/1000= 3.6KW and 5500KW won't handle it??

Something else is going on. Might need to have the generator "Load Tested".

Will the A/C run for a little while and then trip OR Trip when you turn it on? Is it shutting the Generator down or tripping the breaker on the generator?

Tripping the breaker could mean breaker problem. Generator shutting down could be engine problem.

Process of elimination. Good Luck

06 fema trailer-5500w gen problems???
by: loydslade

i dont know if im interrupting the original topic, but i would like some info on generator/camper issue. i just bought a brand new chicago generator 5500RW / 6500 max. the camper is a 30amp hookup. i have been using an ext. cord from my home and it worked. now i have moved into a new home, where it trips the 15amp breaker, "duh i know." my generator will run everything in the camper except for air. even with all the other breakers switched off. and only a/c and main on..it still trips the breaker on gen..please help...und4groundfatal@gmail.com

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