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 > What size generator to run AC??

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Huntindog

Phoenix AZ

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Posted: 06/12/22 08:03am Link  |  Quote  |  Print  |  Notify Moderator

When choosing a generator for AC. the first thing to determine is what degree of reliability do you need?
IOW, if it is hotter than you think it will be, and the generator won't run your AC.... Just how big of a deal is it to you?
I used to compete my Brittanys in AKC field trials I got to see a lot of these kinds of failures.....Numerous times it would be really hot and other peoples generators could not cut it in "real" life situations. They always said the same thing."It worked fine at home"
Add some altitude and heat, and a marginal generator will let you down. A casual camper would likely just go home. A field trial competiter pretty much has too much to lose by going home. I saw a lot of emergency generator upgrades in camp.



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valhalla360

No paticular place.

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Posted: 06/12/22 12:57pm Link  |  Quote  |  Print  |  Notify Moderator

Grit dog wrote:

I agree bigger is better for this application, but if a 2k sounds like a lawnmower, you cheaped out on the purchase.


I may be exaggerating slightly but I've seen more than one of the 2000w units running the air with a soft start and they are anything but quiet.


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supercub

Modesto CA

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Posted: 06/12/22 06:31pm Link  |  Quote  |  Print  |  Notify Moderator

Thanks for the replies, sounds like perhaps the best way is to get a couple of portable 2000 watt gens.

72cougarxr7

Northern NY

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Posted: 06/16/22 09:31pm Link  |  Quote  |  Print  |  Notify Moderator

I went with a Champion 3400 inverter and couldnt be happier!
Quiet, wheels around nicely, electric start so my wife can start it. Runs my ac easily, it sounds like its running at half throttle or less with ac on.
Maintenance is easy. I bought it in 2019 and have not had 1 issue with it.

TomG2

Central Illinois

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Posted: 06/17/22 10:30pm Link  |  Quote  |  Print  |  Notify Moderator

supercub wrote:

Looking at buying a +/-28 foot travel trailer, with one AC unit. What size generator should I have to run the AC and lights, TV, etc?
Thanks


To supercub. Most RV parks and your trailer have 30 amp ratings. 30 X 120 = 3,600 watts. That is what I shoot for if I want the same capability as the shore power in most parks.

Baja Man

Inland Empire, CA

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Posted: 06/27/22 09:49am Link  |  Quote  |  Print  |  Notify Moderator

supercub wrote:

Thanks for the replies, sounds like perhaps the best way is to get a couple of portable 2000 watt gens.


Just what I did.....

Two Champion Dual Fuel 2500W inverters

I didn't want to carry gasoline, clogged carbs from gas sitting, etc.
Propane is clean and readily available.

Each inverter is 39#
dBA is 59 at 23' (Honda is 48-57 at 23')

I believe my set up is great. Light, easy to handle, plenty of power, can use just one if no AC is being used, two fuels, and portable enough for other uses.


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pianotuna

Regina, SK, Canada

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Posted: 06/27/22 11:05am Link  |  Quote  |  Print  |  Notify Moderator

I prefer a single remote electric start generator.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

Gdetrailer

PA

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Posted: 06/27/22 11:22am Link  |  Quote  |  Print  |  Notify Moderator

Baja Man wrote:

supercub wrote:

Thanks for the replies, sounds like perhaps the best way is to get a couple of portable 2000 watt gens.


Just what I did.....

Two Champion Dual Fuel 2500W inverters

I didn't want to carry gasoline, clogged carbs from gas sitting, etc.
Propane is clean and readily available.

Each inverter is 39#
dBA is 59 at 23' (Honda is 48-57 at 23')

I believe my set up is great. Light, easy to handle, plenty of power, can use just one if no AC is being used, two fuels, and portable enough for other uses.


You forgot to mention a few "downsides" of propane for a generator..

First and foremost, propane has less energy density than gasoline, this means your engine will deliver less HP which translates to less generator wattage available per gallon of fuel.

You will burn through a lot more propane in the process, not a big issue if you are not mobile or moving about and can tap into a large propane tank..

20 lb portable cylinders hold a max of 4.6 Gallons of liquid propane, if you use propane "exchanges" you do not get 20 lbs worth of propane, you get max of 15 lbs, roughly 3.6 gallons of propane..

Typically with say a 3Kw gen, you most likely will burn through a full twenty pound cylinder (not an 15 lb exchange cylinder) every 24hrs assuming you run the gen 24/7!

HERE is a website that helps calculate your propane use by a generator..

There are also far, far fewer propane dealers than gas stations and most propane dealers shut their doors after 5 PM and may not be open on weekends. Pretty easy to find gas stations open up to 11 PM or even open 24hrs and open on Sat and Sun..

So, basically one would need to have multiple 20 lb - 40 lb cylinders just for the gen, switching them out to run a gen for a week. Not to mention handling/hauling them around to camp and to a propane dealer while camping. A full twenty pound cylinder weighs approx 38-39 lbs, 5 gallon gas can will weigh around 31 lbs and get longer run time.

valhalla360

No paticular place.

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Posted: 06/27/22 12:56pm Link  |  Quote  |  Print  |  Notify Moderator

Gdetrailer wrote:


You forgot to mention a few "downsides" of propane for a generator..

First and foremost, propane has less energy density than gasoline, this means your engine will deliver less HP which translates to less generator wattage available per gallon of fuel.

It appears you are mixing two things together.
- On propane, the engine will produce less wattage (or HP which is the same thing) but it's nor per gallon. Of course with a 4500w generator or paired 2500w generators, that's a non-issue on a 30amp RV to run the air/con.
- The stored energy per gallon is about run time not maximum wattage.


You will burn through a lot more propane in the process, not a big issue if you are not mobile or moving about and can tap into a large propane tank..

But you will burn thru less gasoline and in a pinch with dual fuel, you can switch back to gasoline.

A 20lb propane tank or a 5 gal gas jug eats up close enough to the same space in the truck bed.


20 lb portable cylinders hold a max of 4.6 Gallons of liquid propane, if you use propane "exchanges" you do not get 20 lbs worth of propane, you get max of 15 lbs, roughly 3.6 gallons of propane..

Yes, the swap places typically give you 15lb but the fill places you get the full amount.

.........

There are also far, far fewer propane dealers than gas stations and most propane dealers shut their doors after 5 PM and may not be open on weekends. Pretty easy to find gas stations open up to 11 PM or even open 24hrs and open on Sat and Sun..

I prefer filling but in a pinch, it's easy to find swap places. Also, I'm filling a tank when it's empty, so I'll just switch to a full tank if it's 11pm.

So, basically one would need to have multiple 20 lb - 40 lb cylinders just for the gen, switching them out to run a gen for a week. Not to mention handling/hauling them around to camp and to a propane dealer while camping. A full twenty pound cylinder weighs approx 38-39 lbs, 5 gallon gas can will weigh around 31 lbs and get longer run time.


Running the generator 24/7 for a week...we'd probably move to a campground in those conditions, so we could plug in. We have 2 tanks on the trailer and 2 in the truck bed. Since 1 tank will easily last us a month or more, in a pinch, we could steal one of the ones off the trailer giving us 3 available for generator use.

If small engines didn't have the carbs get gunked up, I would agree that gasoline is the way to go but the simplicity and reliability of propane shifted us in favor of a dual fuel unit.

Gdetrailer

PA

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Posted: 06/27/22 02:09pm Link  |  Quote  |  Print  |  Notify Moderator

valhalla360 wrote:

Gdetrailer wrote:


You forgot to mention a few "downsides" of propane for a generator..

First and foremost, propane has less energy density than gasoline, this means your engine will deliver less HP which translates to less generator wattage available per gallon of fuel.

It appears you are mixing two things together.
- On propane, the engine will produce less wattage (or HP which is the same thing) but it's nor per gallon. Of course with a 4500w generator or paired 2500w generators, that's a non-issue on a 30amp RV to run the air/con.
- The stored energy per gallon is about run time not maximum wattage.


You will burn through a lot more propane in the process, not a big issue if you are not mobile or moving about and can tap into a large propane tank..

But you will burn thru less gasoline and in a pinch with dual fuel, you can switch back to gasoline.

A 20lb propane tank or a 5 gal gas jug eats up close enough to the same space in the truck bed.


20 lb portable cylinders hold a max of 4.6 Gallons of liquid propane, if you use propane "exchanges" you do not get 20 lbs worth of propane, you get max of 15 lbs, roughly 3.6 gallons of propane..

Yes, the swap places typically give you 15lb but the fill places you get the full amount.

.........

There are also far, far fewer propane dealers than gas stations and most propane dealers shut their doors after 5 PM and may not be open on weekends. Pretty easy to find gas stations open up to 11 PM or even open 24hrs and open on Sat and Sun..

I prefer filling but in a pinch, it's easy to find swap places. Also, I'm filling a tank when it's empty, so I'll just switch to a full tank if it's 11pm.

So, basically one would need to have multiple 20 lb - 40 lb cylinders just for the gen, switching them out to run a gen for a week. Not to mention handling/hauling them around to camp and to a propane dealer while camping. A full twenty pound cylinder weighs approx 38-39 lbs, 5 gallon gas can will weigh around 31 lbs and get longer run time.


Running the generator 24/7 for a week...we'd probably move to a campground in those conditions, so we could plug in. We have 2 tanks on the trailer and 2 in the truck bed. Since 1 tank will easily last us a month or more, in a pinch, we could steal one of the ones off the trailer giving us 3 available for generator use.

If small engines didn't have the carbs get gunked up, I would agree that gasoline is the way to go but the simplicity and reliability of propane shifted us in favor of a dual fuel unit.


Regardless, propane is overall less desirable "alternative" to gasoline when it comes to loss of wattage (the terminology you are looking for is "DE RATED").

Propane contains LESS energy per GALLON than gallon of gasoline.

For instance..

Per HERE

Propane- 1 gallon = 91,452 Btu
Gasoline- 1 gallon = 120,286 Btu

So what you say?

Well less BTU content means less work done and in the case of a generator it takes MORE propane in gallons than gasoline to do the SAME work as gasoline.

Additionally, you get nailed on the price of propane in small portable cylinders since in small cylinders they sell it by the pounds.. Bulk sellers once you get into large tanks sell it by the gallon but unless you want to build a trailer to haul a 250 gallon propane tank with you you are stuck with retail by the pound pricing.

Propane gens also have additional demand regulator, which can foul up, propane doesn't vaporize fast in cold temps which can cause fuel starvation and can even stop vaporizing in cold temps..

Propane isn't always propane, some areas you may get butane at a higher mix in your propane and butane is less BTUs and burns at a slower rate which affects just how well your engine performs and final wattage output.

Something else to consider, "dual fuel" setups are a "COMPROMISE" and overall most small engines are built and tuned for gasoline, the timing and compression are typically optimized for gasoline and not propane..

It sounds good on paper, but in real world use, a compromise is a compromise..

If you don't mind moving 20 lb to 30 lb cylinders (which weigh 38 lbs and 58 lbs each respectively) all the time while camping then have at it, but myself that sounds like a real hassle..

Some of you guys are really way over dedicated to making camping a lot more about doing chores than relaxing.

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