Matching Generator Wattage with Power Requirements

[Streamer1]

Ok, I'm getting close to getting the right size diesel generator that I am interested in. My 2007 25' International uses the popular 30amp power cord like most Airstreams do. My question is, if I get a generator that produces say 6500 watts surge and about 6100 continuous (that's 54.2 amps surge and 50.8 amps continuous, correct?) will the generator "send" its capacity to the trailer and trip the breaker, OR does the Airstream simply "draw" the current it needs to fulfill demand up to its capacity? Basically, can a generator that has more capacity than is required by the trailer "damage" the trailer in any way? What about a generator that is closer to or slightly less powerful, say 3000 watt generator which provides 25 amps? Is this a "worse" situation than having a generator that produces "overcapacity" in terms of excess electricity?

[Excella CM]

You are correct. Power is on demand. You get what you ask for up to the capacity of the generator. A little too much capacity is better than not enough. A generator working at the top end will work harder and wear out sooner.

[Poprivet]

Current is determined by the load, not the generator. No load, no current, no power being consumed (except for friction). Power is a function of current times voltage or P=E X I. 30 amps is roughly 3000 watts {not considering power factor). Using a generator with a higher capacity than needed will not cause damage, just overkill and much heavier.

Most units like yours are designed to operate on the 30 amp cord and have a interlockto prevent operating too many big loads at the same time

[Streamer1]

Thanks for the info everyone.

[SRoffe]

Originally Posted by Pop Rivet

... Power is a function of current times voltage or P=E X I. ...

I like to think of it P=I x E (PIE). Apple suits me...

Seriously though, it seems that a lot on the forum like ganging two 2KW generators such as the Hondas or Yamahas together. I wish I would have went that route.

Sam

[lewster]

Onan is now making a 3200 watt Quiet Diesel model. I had the 6500 watt version in my old Monaco Dynasty MoHo and these units are bullet-proof. They run very quietly, sip diesel and will power your entire trailer nicely.

[Inland RV Center, In]

Originally Posted by Streamer1

Ok, I'm getting close to getting the right size diesel generator that I am interested in. My 2007 25' International uses the popular 30amp power cord like most Airstreams do. My question is, if I get a generator that produces say 6500 watts surge and about 6100 continuous (that's 54.2 amps surge and 50.8 amps continuous, correct?) will the generator "send" its capacity to the trailer and trip the breaker, OR does the Airstream simply "draw" the current it needs to fulfill demand up to its capacity? Basically, can a generator that has more capacity than is required by the trailer "damage" the trailer in any way? What about a generator that is closer to or slightly less powerful, say 3000 watt generator which provides 25 amps? Is this a "worse" situation than having a generator that produces "overcapacity" in terms of excess electricity?

As a rule of thumb, a generator should never be loaded for more than 80 percent of it's rating, except for starting currents.

As an example, a 3000 generator, should not be loaded for more than 2400 watts.

That kind of power demand, will permit your generator to have a long, useful life.

Generators loaded near maximum, usually present many problems in short order.

Andy

[DFord79]

Honda has a wonderfull and quiet (60dbl at full throttle) Eu6500is generator. This is of course more than you might think you need. It weighs approx. 250 lbs but you can put it in the back of a pickup with a Gorilla slide and it works great. Just open the back of your truck and slide the tray out and your genny is outside. It has very stable power, ie. good for computers etc. I thought this would be an over kill for say a 25 foot AS with a 13.5 A/C but I saw this very genny in use two weeks ago at a camp site and I am sold. Its been very hot here in the Northwest this summer and it was being used to power a 27 foot trailer with A/C running all day and elec. hot water tank as well as anything they needed. The great thing about it beside of course having enough power to run ALL THE TRIALER at once was it was little more than idiling most of the time. The only time it ran much about idle was when the A/C was on and they fired up the Microwave with other appliances on at the same time..and even then it didnt run a full throttle. It of course will use a lot of gas at full throttle but with most rv set ups it hardly ever gets to full throttle. The people using it said they absolutely love it after having smaller gennys that had to scream all day long to run the A/C and didn't have enough to run the coffee pot and Micro too. They said it doesnt burn as much gas as they thought it would.....It is just idling running the A/C. I AM SOLD...REGARDLESS OF THE WEIGHT. ITs not that big either...13 HP Honda ...and very quiet. My local dealer has one in stock. He is asking $3695. I have seen ads in magazines with similar prices with free shipping.