Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-01-2012, 12:13 PM   #1
retired USA/USAF

 
2001 30' Excella
Somerset , New Jersey
Join Date: Jan 2009
Posts: 2,157
AC Power draw ?????

I am selling my older AS an purchasing a newer one. I thought I read somewhere that the newer AC units, being more efficient, have a lower power draw than the older ones. My '85s AC seems to be in good working order but needs a 30a power source. The trailer I have purchased, but not picked up yet, is an '02 model. My old one was 13,500 btu's and I think the new one is the same. BUT, is there a possibility that the newer one will run on a 20a service ?????? I have a 2500w generator I take along. It's great for topping up the batteries when needed and watching the TV in the evening but it's a bit under powered to run the AC.

Thanks ALL,
__________________

__________________
Roger in NJ

" Democracy is the worst form of government. Except for all the rest"
Winston Churchill 1948

TAC - NJ 18

polarlyse is offline   Reply With Quote
Old 07-01-2012, 12:21 PM   #2
Rivet Master
 
Bruce B's Avatar

 
2012 16' International
Jamestown , Rhode Island
Join Date: Mar 2012
Posts: 1,387
Images: 1
The 02 has likely got similar power needs to your existing trailer. You may find that the newer a/c unit is more efficient but I am guessing that it is about the same. I am sure it uses a 30 amp service too.

Enjoy the new (newer) Airstream and let us know what you find.

Bruce
__________________

__________________
Barely getting by, towing our 16' Bambi with our Ram 2500 CTD "Moby"!
Bruce B is offline   Reply With Quote
Old 07-01-2012, 12:43 PM   #3
retired USA/USAF

 
2001 30' Excella
Somerset , New Jersey
Join Date: Jan 2009
Posts: 2,157
Thanks Bruce. You're not telling me anything that I didn't already think I knew. Perhaps it was wishful thinking. During the summer I try to travel to places where AC use is minimal. Like high altitudes and this summer will be no exception but you got to get there first. And sometimes ( usually) that means places where it's nice to have the AC. I'm heading west in a week and that's where the new trailer is. So at the end of the month we'll be off to GNP and points west and high.

Thanks for the input.
__________________
Roger in NJ

" Democracy is the worst form of government. Except for all the rest"
Winston Churchill 1948

TAC - NJ 18

polarlyse is offline   Reply With Quote
Old 07-01-2012, 01:00 PM   #4
tpi
Rivet Master
 
2005 25' Safari
Trabuco Canyon , California
Join Date: Apr 2006
Posts: 866
Images: 2
I've used 30 amp, and used the adapter to use 20 amp outlet successfully with the AC. No problems. The line draws at 15 amp circuit, the breaker will pop in any 15 amp service I tried.

Voltage in all cases, measured in trailer was good.

One minor thing you can do to insure the AC will run is select gas for the refrigerator. It saves a couple hundred watts. Another is to ensure your batteries are not deeply discharged. A heavy charge load is undesirable in this circumstance.
__________________
tpi is offline   Reply With Quote
Old 07-01-2012, 01:57 PM   #5
Rivet Master
 
1974 Argosy 20
2014 20' Flying Cloud
Kooskia , Idaho
Join Date: Jul 2009
Posts: 4,591
If you look at the RV AC manufactures web sites directly you will see that some of them have a high efficiency unit with significantly lower power draw than the conventional models. The difference is significant with the high efficiency 13,500 btuh ones requiring 10 to 10.5 amps vs. the 13.5 to 14 amps of conventional ones.

Why are they not more common? RV manufactures require lowest costs from their suppliers, and the high efficiency units have a slightly higher cost (about $50). Since there is no real "demand" from the purchasers, they don't buy them. Purchasers generally don't care how efficient their AC unit is, they think that their campground electricity is Free, as it is part of their campground fee.

There is also no governmental regulations on the efficiency of RV AC units, as there is on all window units and home units, so the manufactures can continue to make the inefficient ones and no one cares.

Rant off: But you can buy some higher efficiency AC units which will require less power when you are plugged in, and will allow you to use a smaller generator when boondocking. You just have to look harder for them and find someone who stocks them or will get one for you. Look at the amp draw figures, you will see the difference I mention above, but not everyone makes them, which is sad.
__________________
idroba is offline   Reply With Quote
Old 07-09-2012, 09:52 AM   #6
Rivet Master
 
TouringDan's Avatar

 
1966 24' Tradewind
1995 34' Excella
Lynchburg , Virginia
Join Date: Sep 2009
Posts: 2,472
I would say that a 2500 watt generator should run your AC especially if you power your fridge and water heater with propane. I would power the tv using your batteries and an inverter. I can not imagine starting up a generator just to watch tv. Most tv's take only 50-75 watts to operate.

Dan
__________________
TouringDan is offline   Reply With Quote
Old 07-09-2012, 11:12 AM   #7
4 Rivet Member
 
2012 25' Flying Cloud
Eureka , California
Join Date: Sep 2011
Posts: 321
I think this Dometic model will run on a 20A circuit.

Products - Dometic
__________________
redwoodguy is offline   Reply With Quote
Old 07-09-2012, 12:25 PM   #8
Rivet Master
 
1974 Argosy 20
2014 20' Flying Cloud
Kooskia , Idaho
Join Date: Jul 2009
Posts: 4,591
The first one, the "high efficiency" 459530 shown on this page is the one with lower current draw. It is a 13,500 btuh unit, I think their page designer screwed up and didn't list it.

You can see, the compressor only draws 8.6 amps vs. 12.4 amps for the standard unit. The fans in both draw 2.5 amps. So, the high efficiency one uses 11.1 amps to run and the standard (lets call it the low efficiency one) 14.9 amps. Same cooling capacity.

http://www.dometic.com/10436664-32fa...538a1dcc.fodoc

Since this is not the normal AC unit, you will not get the higher efficiency unless you specifically specify the 459530. Your '02 rig you will be picking up will have the regular (not high efficiency) unit in it, I am virtually positive. Again, I find it sad that the standard 13,500 btuh RV AC units are still out there, when for a small amount of money more they all could be the high efficiency ones, drawing about 30% less power for the exact same cooling capacity.
__________________
idroba is offline   Reply With Quote
Old 07-09-2012, 01:46 PM   #9
Don't forget your cat nap
 
Ag&Au's Avatar
 
Port Orchard , Washington
Join Date: May 2009
Posts: 4,464
Images: 1
You can, and I have run the A/C on 20 amp service. However, you must check to be sure voltage present in the trailer is within the acceptable range when the A/C is being used. Obviously various factors affect the voltage.

Now, that being said, I would not recommend it at all as a common practice. I only do it at home for the purpose of testing the A/C. I monitor the voltage at all times and make sure no other AC appliance is operating.

I have a 15,000 BTU A/C.

Ken
__________________
Ag&Au is offline   Reply With Quote
Old 07-09-2012, 02:16 PM   #10
Wise Elder
 
Jammer's Avatar
 
2010 30' Classic
Vintage Kin Owner
South of the river , Minnesota
Join Date: Dec 2009
Posts: 4,119
Quote:
Originally Posted by polarlyse View Post
I am selling my older AS an purchasing a newer one. I thought I read somewhere that the newer AC units, being more efficient, have a lower power draw than the older ones.
In most cases there's little difference. The new A/C isn't especially efficient because of the small size of the condenser and evaporater compared to the high efficiency units you would have in a house.

Quote:
My '85s AC seems to be in good working order but needs a 30a power source. The trailer I have purchased, but not picked up yet, is an '02 model. My old one was 13,500 btu's and I think the new one is the same. BUT, is there a possibility that the newer one will run on a 20a service ??????
If you run the fridge on gas and turn off the converter, and don't run any other appliances, you should be able to run the A/C on your '85 on 20 amp service. That is also true for your new trailer.

Quote:
I have a 2500w generator I take along.
That's a different question. Most 2500w generators can't start a 13,500 BTU/h air conditioner, at least not on a hot day at altitude.
__________________
To learn to see below the surface, you must adjust your altitude
Jammer is offline   Reply With Quote
Old 07-09-2012, 02:16 PM   #11
Rivet Master
 
Silver Otter's Avatar

 
2011 31' Classic
Nellysford , Virginia
Join Date: Mar 2011
Posts: 979
Images: 6
Blog Entries: 1
Ken,
I'd like to do that here at The Cabin. I have a dedicated 20 amp line I can use. You mentioned a voltage range. I can "see" my incoming voltage on my Progressive box. What range is good? What is too low? THANKS.
__________________
Greg and Linda Heuer
2011 31' Classic Ltd. - The Silver Otter III
2013 GMC Denali 2500HD 6.6 DuraMax
TAC VA-18 | WBAC 1927 - Shen. Valley Unit 149 | AIR 53869
https://www.linkedin.com/in/gheuer
Silver Otter is offline   Reply With Quote
Old 07-09-2012, 02:32 PM   #12
Wise Elder
 
Jammer's Avatar
 
2010 30' Classic
Vintage Kin Owner
South of the river , Minnesota
Join Date: Dec 2009
Posts: 4,119
Greg

Check the voltage with the A/C running.

If it's 117 volts then your A/C will draw about the rated current, around 15.2 amps. (The published Dometic current ratings are based on a 115 volt supply voltage but you'll probably lose 2 volts from the breaker box to the A/C). Happy happy.

If it's 110 volts then your A/C will draw maybe 10% more than the rated current, say, 17 amps. So far so good. The 10% figure is based on a combination of the tendency of A/C electric motors to draw proportionally more current when the voltage delines, and the slight loss of efficiency when the voltage moves away from the design voltage.

If it's 100 volts then your A/C will draw maybe 20% more than the rated current, say, 18 amps. Now you might blow a breaker, especially if the fridge or the converter is drawing a couple of amps.

If it's 90 volts then your A/C will draw 30% more than the rated current, say, 20 amps or so. At this point the breaker will pop eventually although it may take a couple of hours. Also, if the voltage drop is this great, the A/C may not start.

Anything below that and the A/C compressor isn't going to start, and the thermal overload will (hopefully) trip.
__________________
To learn to see below the surface, you must adjust your altitude
Jammer is offline   Reply With Quote
Old 07-09-2012, 02:43 PM   #13
Don't forget your cat nap
 
Ag&Au's Avatar
 
Port Orchard , Washington
Join Date: May 2009
Posts: 4,464
Images: 1
Quote:
Originally Posted by Jammer View Post
Greg

Check the voltage with the A/C running.

...................................


. Also, if the voltage drop is this great, the A/C may not start.

Anything below that and the A/C compressor isn't going to start, and the thermal overload will (hopefully) trip.
__________________
If I provide a useful answer for your question and you don't thank me in some fashion, the Karmic burden will follow you for the rest of your life

I will thank you for answering it better than I could and saving me the embarassment of saying "standby while I look it up"

I have a voltmeter plugged into a wall socket. I make sure the needle stays in the green area on the scale.

Ken
__________________
Ag&Au is offline   Reply With Quote
Old 07-09-2012, 03:03 PM   #14
Rivet Master
 
Silver Otter's Avatar

 
2011 31' Classic
Nellysford , Virginia
Join Date: Mar 2011
Posts: 979
Images: 6
Blog Entries: 1
Hey both of you . . . Good advice. I'll check it out after this storm passes. THANKS!
__________________

__________________
Greg and Linda Heuer
2011 31' Classic Ltd. - The Silver Otter III
2013 GMC Denali 2500HD 6.6 DuraMax
TAC VA-18 | WBAC 1927 - Shen. Valley Unit 149 | AIR 53869
https://www.linkedin.com/in/gheuer
Silver Otter is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 03:10 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.