generator size


New Member
We have a 37 foot triple slide toyhauler with a 15,000 btu air conditioner. We are looking at buying a generator and was wondering what size to get. We are looking at buying a 3500 watt and was wondering if that would be big enough. I don't care if I can run my air and microwave at the same time.
Thank you


Senior Member
Re: generator size

Look at it this way: is the trailer 30 amp or 50 amp? If the trailer is 30 amp, then anything over 3600 watts is wasted, because the trailer can't handle any more wattage (30 amps x 120 volts) anyway. So 3500 should be adequate. If the trailer is 50 amp, then 12KW would be the MAXIMUM you would need, but in reality, 7.5KW is generally plenty even with 2 AC units. Less then that is certainly possible, but starts to require you to be more carefull of what you use, electrical load wise.

I suspect 3500 will run most single air conditioners. If the AC won't start reliably on 3500, install an 'easy start' kit in the air conditioner. This is a capaciter which is charged up and a relay, to add the capacitor to the start circuit to give it an extra initial 'kick'. On my 25' trailer, it allowed me to get by with a 3000 watt generator which could not kick over the compressor when it had 'rested' in a particular position for a while.

DL Rupper

Senior Member
RE: generator size

Hey r3499, welcome to the forum. I have a 30' 2 slide 5'er with a 15,000btu A/C and use an onboard ONON 4000 watt generator and have no problems. However, if I were to do it over, I would buy 2 Honda 2,000 watt portable generators and run them in parallel if you are using the A/C. If you are not using the A/C you would probably only need to run 1 generator. Alot of RV'ers are doing that now. The Hondas run about $1K each and the parallel hookup runs about $250. Just an option you might want to consider.

Grandview Trailer Sa

Senior Member
Re: generator size

I have a Honda 3000 and it runs my 50 amp, 35' fiver just fine. I do realize I can't run everything at once, but just this past weekend we had no problems.

We went to a Virginia Tech football game and set up in a parking lot Friday afternoon. That afternoon we had our 15K AC on but by Sat. night we were running the furnace and electric fireplace. We also ran hair dryer, curling iron, coffee maker, 2 TV's and microwave. I did have the refer and water heater on gas, and again, we did not run all electrical items at once.

Use a little common sense, and you will get along just fine. IF you want to run a lot of things at once, of course you need a bigger unit, but I used mine from Friday afternoon to Sunday morning on about 6 gallons of gas.