Running 2ac's on 30amp

[salzerj@comcast.net]

Many 30 amp coaches run two air conditioners with no problem...but you're right. Beyond the two AC's you have too be frugal!

[Bill Johnson]

Originally Posted by Chance

Both inside and outside temperatures make a huge difference. See Coleman data below that “approximates” effect outside temperature makes. There’s other data for inside temperature. This isn’t that accurate so don’t take it as an exact correction.

Note also on 13,500 BTU/hour Power Saver data above that standard running Watts is 1,075 but that desert conditions is 1,320 Watts. Assuming same efficiency, power factor, and that voltage is reduced from 115 to 103.5 VAC per desert rating conditions, current would go from 10 Amps to over 13 Amps.
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I just saw the same thing, so in my area 95 would be the high and that would be RLA let's say 13 amps at 80 degrees it would be about10 amps

[lwmcguir]

Originally Posted by Chance

The best news is how much air conditioners have improved in efficiency, and that there’s still theoretical room for even more improvement.



A few years ago Coleman advertised how their 13,500 BTUH A/C reduced current from 15.3 to 11.2 Amps, and now they have specs showing 10 Amps. That 10 Amps is 1,075 Watts, which represents an EER of 12.5. There’s definitely room to make that EER much higher and thus reduce electrical requirements below 10 Amps.



Even at 10 Amps, two units for a total of 20 Amps is quite below 30A service.





P.S. — I’m a little skeptical about 10A rating and would want to see/measure myself, but even if close, it’s pretty good.

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My 1500 watt units draw 12 amps on high typically

Maybe an amp difference between the three at 120v per line

You can watch the amps climb when a camp ground has a high load

[lwmcguire]

We have several large heat pumps at one home

The only correct to charge a 410a system is to use the sub cooling value for that particular compressor

Both outside and inside temperatures affect a compressor and condensr performance

You have to monitor the high side temp along with pressure to accurately charge

High temperatures do result in higher amp draw

[Jimbo56]

Originally Posted by Rcstroll

Hi! Have 50 amp as well. Was able to use 2 a/c units on it and thought that i was doing great! I was... after 3 days of such use, broke camp and ...wow! The cables were super hot and the 50 to 30 cable burning hot!! Just pray I didn't do any damage. Never again... even if it works....

Yep. I melted a dogbone several years ago. Lucky nothing was damaged. So regardless of all the arithmetic calculations, I’ll stick to one AC and just sweat a little more in July in the Southeast.

[Bob Denman]

That's why they invented "Sweet Tea" down South anyway...

[Chance]

Originally Posted by Jimbo56

Yep. I melted a dogbone several years ago. Lucky nothing was damaged. So regardless of all the arithmetic calculations, I’ll stick to one AC and just sweat a little more in July in the Southeast.

What do you think happened? You are not providing much information other that it involved 2 A/Cs. I don’t know how else to say that all A/Cs are not the same and can’t be treated as equals in “calculations”.

Regardless, the obvious questions are that if you exceeded 30A, why didn’t the breaker trip. And if you remained under 30A, then why did a 30A dogbone melt?

Proper electrical systems have protection so they remain safe even if owner overloads it. I wouldn’t blame the math when something else went wrong. Besides, we’d still be in the Dark Ages if not for math and wouldn’t be enjoying air conditioning at all.

[TurnerFam]

good question, CHANCE, as these are the types of 'stories' that easily lead to misinformation about how electricity 'works' - the owner does not understand that simply running two a/c units, or two of anything, has nothing to do with a 'melted' connector, etc. If a connection has an issue, it's with the wiring and connector, NOT the fact that the power was somehow 'overloaded' or anything - a loose neutral wire is a typical issue that cause overheating and melting within plastic housings, not the use of a/c units.

[16ACE27]

Originally Posted by TurnerFam

good question, CHANCE, as these are the types of 'stories' that easily lead to misinformation about how electricity 'works' - the owner does not understand that simply running two a/c units, or two of anything, has nothing to do with a 'melted' connector, etc. If a connection has an issue, it's with the wiring and connector, NOT the fact that the power was somehow 'overloaded' or anything - a loose neutral wire is a typical issue that cause overheating and melting within plastic housings, not the use of a/c units.

So do dirty/corroded connections - anything that causes the dogbone connection to have a higher than normal resistance will cause heat at that connection and the heat goes up exponentially as the current goes up.

[lwmcguire]

I don't think that there is anyone that has camped a number years that hasn’t melted a couple of adapters and dog bones

Not trying to run e ac's necessarily either

[Jimbo56]

I was in a 50 amp fifth wheel. One carrier AC. Using a 50 to 30 dogbone. A county park camp ground. Might have been a dirty connection. Maybe a loose wire in the pedestal. I don’t know. I didn’t try to diagnose it due to check out time. All I do know is that it was hot and gooey feeling when I turned the breaker off and went to pull it out of the plug. This coach is 30. I’ve done everything to make the one unit as efficient as possible. When in 98 degree high humidity with no shade, I can get it to 78. So I’m fine. Just sayin.

[Jimbo56]

Originally Posted by TurnerFam

good question, CHANCE, as these are the types of 'stories' that easily lead to misinformation about how electricity 'works' - the owner does not understand that simply running two a/c units, or two of anything, has nothing to do with a 'melted' connector, etc. If a connection has an issue, it's with the wiring and connector, NOT the fact that the power was somehow 'overloaded' or anything - a loose neutral wire is a typical issue that cause overheating and melting within plastic housings, not the use of a/c units.

I was not trying to spread misinformation. Only responding to the guy who had a similar experience. I camp & travel for fun and enjoyment. Period.

[Chance]

For what it’s worth (and we are all just sharing information in case it helps others in some way) the Forest River Sunseeker line of Class Cs is also offering dual high-efficiency air conditioners with 30A service. Along with Thor and others, it’s now fairly common in what appears to be mid-size modest-cost motorhomes. Larger and higher-end gasoline rigs mostly continue to have 50A and 5,500 in lieu of 4,000-Watt generators that come with 30A electrical in these size motorhomes. The smaller generator should save both weight and cost.
.

[Esqui]

Hello all,

So I'm in the process of buying a new 2021 Jayco Alante 29f and I have a question. The coach has two 11,000 BTU A/C units but a 30 amp service. Has anyone had a problem with this? Can anyone explain how Jayco is able to do this? I've always been of the mindset that two A/Cs required 50 amps.

Thank you in advance,

Esqui

[Pete'sMH]

Originally Posted by Esqui

Hello all,

So I'm in the process of buying a new 2021 Jayco Alante 29f and I have a question. The coach has two 11,000 BTU A/C units but a 30 amp service. Has anyone had a problem with this? Can anyone explain how Jayco is able to do this? I've always been of the mindset that two A/Cs required 50 amps.

Thank you in advance,

Esqui

Well they’re smaller units and the energy management system certainly will help manage start up loads and maybe even sequence the start up or operation of the two units. Possibly they take turns actually cooling though I don’t think that would be very satisfactory for most people. In any event it probably is sort of marginal. Running your water heater on electric and using the microwave might be iffy. On the other hand you’ll probably only need both ACs during the heat of the day and you might well be able to manage your other demands accordingly. But all of that is a guess. Try before you buy!!

[Down South]

Originally Posted by Pete'sMH

Get one of these for about $10 and keep it plugged into a convenient outlet so you can keep an eye on park voltage. I’ve seen 107 during a hot day and 122 in the same park on the same day at night. I keep it in the bathroom and it’s just right for a night light as an added bonus. Autoformer is a bit pricey but is a useful addition to any coach.[ATTACH]26171

Thanks for the heads up. I have an EMS but I have to go outside and wait for it to cycle to volts to see what the current volts are at the time.
I can plug this little gem up inside the MH "Kitchen" and see my volts easily at a glance.
I ordered one from Amazon. They are $15 now.

[cavie]

Originally Posted by mrgscooter

Have a 50amp MH, thought could only a single ac unit on 30amps, first time at 30amp hookup and both work. I realize probably can't run much else with both units running however to just cool the MH on a hot day works great. Is this typical or is there anything special maybe on pedestal?

nope ANY RV should be able to run 2 A/C's with nothing else running.

[Down South]

It doesn't take long to figure out that electric on the water heater + AC + Microwave = tripped breaker.

[kwplot34]

I tried to run our 2020 Omni XG32 air conditioners on a 30 amp circuit just to see if it would do it, and it wont. Turned on the main coach a/c first waited a couple of minutes and turned on the a/c in the bedroom, and the system shut off the main coach a/c then turned on the bedroom a/c. so something in the touch pad controller or somewhere in the coach it will not allow to run both on 30 amps.

[Chance]

NOT ALL AIR CONDITIONERS ARE THE SAME


The ones being questioned on Jayco are 11,000 BTU/hr Power Savers (energy efficient). They are rated under 11 Amps each under normal conditions if I recall correctly, so well under 30 Amps combined.

Standard 15,000 BTU/hr air conditioners can pull between 15 and 20 Amps each, so two CAN NOT run on 30A service. Details do matter.

Specs show MH comes with load shedding. One A/C should turn off under heavy loads, like when microwave is turned on. I’d confirm myself, and wait for A/C to come back on automatically after microwave shuts off. There may be a time delay, so give it time if A/C was off just for short period.