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06-29-2016, 11:58 AM
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#1
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Senior Member
Monaco Owners Club Entegra Owners Club
Join Date: Feb 2016
Posts: 151
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Question about running AC's in extreme heat
Hello all,
Last week we were driving across the Imperial Valley area in the record 118 degree heat. Needless to say, that kind of heat pushes everything to its limits. We have a 10K generator that never shut down during the heat but it would blow the 45amp breaker on the generator if we ran all three roof AC's. So we switched the fridge over to LP and only ran the front roof air and never had any further issues.
I was told that in that kind of heat, the AC's pull a lot more amps than they normally do and so there is no chance of running all three off the generator. The example I was given was that normally they each pull about 12 +/- amps but in extreme heat that number could be as high as 19 amps. I was also told if we were parked, we would have the same problem with 50amp shore power in heat above 110 or so.
My question - does this sound correct? Obviously our goal is to stay out of that kind of heat but hey, we live in Phoenix so getting out of town in the summer can be hot until we get to higher ground or the beach! Additionally, we usually fire up the RV about 48 hours before we hit the road to load it, get the fridge cold etc so it would be nice to know my limits on power consumption in our summer heat. Our previous coach had 50amp service but only 2 AC's so we never had a problem.
Thanks for your input.
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RV'ing as much as work will allow!
Michael & Kathy, Scottsdale, AZ
2020 Entegra Aspire 44B
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06-29-2016, 12:14 PM
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#2
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Senior Member
Fleetwood Owners Club Outdoors RV Owners Club
Join Date: Nov 2013
Location: Houston, Texas
Posts: 4,580
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Yeah, heat can put a strain on the systems.. but I would think you could run two a/c no problem
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RVM#78 - -USAF- F-15 Eagle Radar Vet
'5 Fleetwood Revolution- '15 Airstream Intl Sig. 27FB
Jay, Andrea, Stella '14 Ram 3500 Aisin '18 ORV F30RLS
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06-29-2016, 12:14 PM
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#3
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Senior Member
Join Date: Oct 2012
Posts: 2,328
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Something doesn't sound right. First, not sure why the A/C would pull more just because it is hot outside. Second, even of all three A/C pulled 20 amps each (not likely) that would be only 60 amp total. Your generator puts out two 45 amp legs for a total of 90 amps.
On shore power the 50 amp service Has two legs of 50 amp each for a total of 100 amp. More that enough to run everything in your coach at the same time.
Not sure what is wrong but something is not right.
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Paul, Kathy, and Tux the Mini Schnauzer
2014 Tiffin Phaeton 42 LH, 2013 Honda CRV
"When the time comes to look back, make sure you'll like what you see"
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06-29-2016, 12:25 PM
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#4
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Senior Member
Join Date: Jul 2014
Posts: 35,442
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Quote:
Originally Posted by Selah
Something doesn't sound right. First, not sure why the A/C would pull more just because it is hot outside. Second, even of all three A/C pulled 20 amps each (not likely) that would be only 60 amp total. Your generator puts out two 45 amp legs for a total of 90 amps.
On shore power the 50 amp service Has two legs of 50 amp each for a total of 100 amp. More that enough to run everything in your coach at the same time.
Not sure what is wrong but something is not right.
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I have seen 20 amps on my AC, before I cleaned the coils on the roof. It was only in the high 80s that day.
The hotter the ambient air, the higher the refrigerant pressure. Higher pressure equels more current draw.
Although there is 90 amps, 2 of the AC units must share a 45 amp leg.
If anything else is running, that puts them close to the threshold of the breaker.
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06-29-2016, 12:32 PM
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#5
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Senior Member
Winnebago Owners Club Freightliner Owners Club
Join Date: Sep 2012
Location: CO
Posts: 934
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And don't forget the Refrigerator. It probably has the same additional draw in heat as the A/Cs
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Colorado '15 Winnebago Forza 34T w/MKZ hybrid toad '20 Jeep Cherokee Trailhawk toad
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06-29-2016, 01:58 PM
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#6
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Senior Member
Fleetwood Owners Club Freightliner Owners Club
Join Date: Nov 2010
Location: Texas
Posts: 4,283
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15 Discovery
Never seen our Very High Efficiency A/Cs pull over 8 amps each. Even extremely hot out. With 3 A/Cs it should never pull more than our 8K water cooled generator can produce.
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06-29-2016, 01:59 PM
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#7
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Senior Member
Monaco Owners Club Entegra Owners Club
Join Date: Feb 2016
Posts: 151
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Quote:
Originally Posted by Gormleys
And don't forget the Refrigerator. It probably has the same additional draw in heat as the A/Cs
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Exactly! That's why I mentioned that we switched it over to LP.
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RV'ing as much as work will allow!
Michael & Kathy, Scottsdale, AZ
2020 Entegra Aspire 44B
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06-29-2016, 02:00 PM
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#8
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Senior Member
Monaco Owners Club Entegra Owners Club
Join Date: Feb 2016
Posts: 151
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Quote:
Originally Posted by twinboat
I have seen 20 amps on my AC, before I cleaned the coils on the roof. It was only in the high 80s that day.
The hotter the ambient air, the higher the refrigerant pressure. Higher pressure equels more current draw.
Although there is 90 amps, 2 of the AC units must share a 45 amp leg.
If anything else is running, that puts them close to the threshold of the breaker.
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That is how I understood it when it was explained to me.
__________________
RV'ing as much as work will allow!
Michael & Kathy, Scottsdale, AZ
2020 Entegra Aspire 44B
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06-29-2016, 02:02 PM
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#9
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Senior Member
Monaco Owners Club Entegra Owners Club
Join Date: Feb 2016
Posts: 151
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Quote:
Originally Posted by Fiesta48
Never seen our Very High Efficiency A/Cs pull over 8 amps each. Even extremely hot out. With 3 A/Cs it should never pull more than our 8K water cooled generator can produce.
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I have never had a problem with ours in in the past. However, I have never been running all three in 118 degree heat before this. 105, yes. 110, yes. Never 118.
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RV'ing as much as work will allow!
Michael & Kathy, Scottsdale, AZ
2020 Entegra Aspire 44B
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06-29-2016, 03:49 PM
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#10
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Senior Member
Join Date: Jul 2015
Location: Athol, Id
Posts: 126
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Any appliance, AC, Refer, Range, Dryer etc should never draw more current (amps) than the listing on the label.
If it does it should shut down or trip the breaker.
This is a UL listing thing !!!!!!!!!!
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2008 Dutch Star 4035
Retired IBEW Local 595
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06-29-2016, 03:55 PM
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#11
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Moderator Emeritus
Monaco Owners Club Texas Boomers Club
Join Date: Nov 2015
Location: Central Texas
Posts: 13,426
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A properly working A/C shouldn't draw more amperage than the label states it will draw. A dirty coil or failing compressor could cause the current draw to go up. You may have an issue with one of your A/Cs.
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Dennis and Katherine
2000 Monaco Dynasty
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06-29-2016, 04:00 PM
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#12
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Senior Member
Join Date: Jan 2014
Location: Safety Harbor, FL
Posts: 2,528
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Quote:
Originally Posted by Selah
Something doesn't sound right. First, not sure why the A/C would pull more just because it is hot outside.
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The hotter the temperatures the hotter the refrigerant is this means it take more power to compress it the same hence higher load.
For instance the Coleman Mach 15 on my RV is rated to draw 1650 watts at 95F outside and 1900 watts at 115F outside.
Temperature most definitely effects amp draw.
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2022 Thor Palazzo 33.5
2016 Jeep Wrangler Unlimited Rubicon Toad - Readybrute Elite Towbar
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06-29-2016, 04:02 PM
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#13
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Senior Member
Country Coach Owners Club Solo Rvers Club iRV2 No Limits Club
Join Date: May 2011
Location: Vancouver, WA
Posts: 37,725
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Quote:
Originally Posted by Selah
On shore power the 50 amp service Has two legs of 50 amp each for a total of 100 amp. More that enough to run everything in your coach at the same time.
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Ours will draw more than 100 amps if I turn everything on but our dryer is 220 volts.
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2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft, HWH Active Air
Charter Good Sam Lifetime Member, FMCA,
RV'ing since 1957, NRA Benefactor Life, towing '21 Jeep JLU Rubicon Ecodiesel
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06-29-2016, 04:07 PM
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#14
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Senior Member
Monaco Owners Club Entegra Owners Club
Join Date: Feb 2016
Posts: 151
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Quote:
Originally Posted by Dutchstar08
Any appliance, AC, Refer, Range, Dryer etc should never draw more current (amps) than the listing on the label.
If it does it should shut down or trip the breaker.
This is a UL listing thing !!!!!!!!!!
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No need to yell.
Each AC unit is on its own 20amp breaker so I will assume they are rated up to 20amps. None of those tripped so I will assume that none of the individual AC's ever exceeded 20amps.
And...based on my description in my initial post, the breaker on the generator did properly trip when the three AC's running together exceeded the generator's max load.
This is what lead to my question of - Could the excessive heat cause each AC unit to increase its load enough(but still be within it's acceptable operating range) that when all running together, they exceed the generator's capacity?
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RV'ing as much as work will allow!
Michael & Kathy, Scottsdale, AZ
2020 Entegra Aspire 44B
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