Reply
 
Thread Tools Search this Thread Display Modes
 
Old 05-20-2015, 02:00 AM   #1
Rivet Master
 
2016 30' International
Scottsdale , Arizona
Join Date: Jul 2010
Posts: 723
Run fridge on 110v (inverter) while driving?

We don't have our Airstream yet, but I was wondering... with the 1000w inverter in the new Airstreams, do the batteries get charged by the tow vehicle's electrical connection while the Airstream is being towed?

And, given that battery charging while driving, would the 1000w inverter be able to run the fridge on 110v, inverted from the batteries that are being charged while the trailer is being towed?

In other words, rather than consume propane to run the fridge while in travel, wouldn't the fridge run off the inverter, from the batteries being charged while driving the TV?
__________________

__________________
DHart is offline   Reply With Quote
Old 05-20-2015, 04:30 AM   #2
Rivet Monster
 
wahoonc's Avatar

 
1975 31' Sovereign
1980 31' Excella II
Sprung Leak , North Carolina
Join Date: Jun 2003
Posts: 7,174
Images: 40
Unless something has drastically changed; the answer is no. The fridge will most likely drain the batteries faster than the tow vehicle can recharge them. However there are several variables.

Aaron
__________________

__________________
....so many Airstreams....so little time...
WBCCI #XXXX AIR #2495
Why are we in this basket...and where are we going
wahoonc is offline   Reply With Quote
Old 05-20-2015, 06:12 AM   #3
Rivet Master
 
Skater's Avatar
 
1995 30' Excella
Bowie , Maryland
Join Date: Apr 2005
Posts: 2,344
Quote:
Originally Posted by wahoonc View Post
Unless something has drastically changed; the answer is no. The fridge will most likely drain the batteries faster than the tow vehicle can recharge them. However there are several variables.
Yeah, this is the answer. The charge line doesn't contribute much, while the fridge draws quite a bit on electric mode, plus losses in the inverter. I've done it, but even with 3 batteries and a large solar system, my batteries were pretty run down by the time we got to the site, and we only did it for a few hours. (We were going through a tunnel where we had to shut off the propane, and it was a blazing hot day, so I tried that solution.)
__________________
1995 Airstream Classic 30' Excella 1000
2014 Ram 2500 Crew Cab with Cummins 6.7L Diesel

Sold but not forgotten: 1991 Airstream B190
Sold: 2006 F-250 6.0L Powerstroke Supercab
Skater is offline   Reply With Quote
Old 05-20-2015, 09:21 AM   #4
Rivet Master
 
1974 Argosy 20
2014 20' Flying Cloud
Kooskia , Idaho
Join Date: Jul 2009
Posts: 4,591
The 120 volt heating element in the refrigerator takes about 300 watts depending on the size of the refrigerator. The inverter is about 90% efficient in converting from 12 volts, so you would then have an input of about 330 watts. At 12 volts 330 watts is around 28 amps.

The charge from the tow vehicle through the cord can be as low as 6 amps, and I have never seen mine larger than 12 amps with new vehicles and virtually perfect electrical plugs. So, any difference comes from the RV battery.

Trust me, it will not hold up long with that rate of discharge. (about 20 amps).

BTW, the heating element in an absorption refrigerator such as RV's use is on a great deal of the time, especially in warmer weather. That is, it really averages close to maximum 300 watts in most situations.

RV refrigerators are very inefficient operated on 120 volt power. While a modern large household compressor refrigerator may average less than 100 watts an hour, the much smaller RV refrigerators I have measured come in over 250 watts an hour.

Bottom line, use propane to power the refrigerator while towing.
__________________
idroba is offline   Reply With Quote
Old 05-20-2015, 09:35 AM   #5
3 Rivet Member
 
ckottum's Avatar
 
2012 25' Flying Cloud
Battle Lake , Minnesota
Join Date: Mar 2015
Posts: 231
Our fridge is always on propane when traveling, has never failed us and doesn't use much propane. Freezer and fridge sections work perfectly in this mode.

cheryl
__________________
ckottum is offline   Reply With Quote
Old 05-20-2015, 11:52 AM   #6
4 Rivet Member
 
dames7's Avatar

 
2015 25' Flying Cloud
GILBERT , Arizona
Join Date: Jan 2015
Posts: 376
Blog Entries: 2
Can someone tell me how much propane will I use to run the frig. on a 8 hour drive, I have a 2015 25ft Flying Cloud.
__________________
dames7 is offline   Reply With Quote
Old 05-20-2015, 12:00 PM   #7
Rivet Master
 
Skater's Avatar
 
1995 30' Excella
Bowie , Maryland
Join Date: Apr 2005
Posts: 2,344
Quote:
Originally Posted by dames7 View Post
Can someone tell me how much propane will I use to run the frig. on a 8 hour drive, I have a 2015 25ft Flying Cloud.
Probably not even enough to measure. A single 30 lb propane tank will run the fridge for weeks, if not months. Of course there's some variation in usage depending on how much the fridge has to work to stay cool (you'll use less in cold weather than warm, for example). But I wouldn't even worry about the amount of usage you're describing. We had ours running for an entire weekend on propane, along with some furnace and water heater usage, and we still used only used a couple pounds of propane.
__________________
1995 Airstream Classic 30' Excella 1000
2014 Ram 2500 Crew Cab with Cummins 6.7L Diesel

Sold but not forgotten: 1991 Airstream B190
Sold: 2006 F-250 6.0L Powerstroke Supercab
Skater is offline   Reply With Quote
Old 05-20-2015, 12:01 PM   #8
1 Rivet Member
 
1964 24' Tradewind
Fallon , Nevada
Join Date: Apr 2010
Posts: 10
The answer, with relatively simple modifications, is yes. I've towed my Avion with Dometic 3 way for 30,000+ miles using the 12v heaters. There are only a couple of amps difference in the requirements. The answer is a #8 charge line in the vehicle so that the vehicle can supply the necessary current. Nearly all vehicles are set up with a wimpy charge setup. It was a delight not to have to screw around with propane all the time. Unfortunately, the 12 volt heaters are a little lower wattage than the 110 volt heaters, So, the cooling effect is only adequate. You can't load up with warm stuff and expect the fridge to cool down very well. On the other hand, the refrigerators are designed to run with the 110 volt heaters. If the charge supply is properly set up, it'll work fine.

It is true that absorption refrigerators are energy inefficient. But it works.

There can be much more to the whole quandary, but that's the simple answer.

Roland Hyatt
__________________
wrhjr3 is offline   Reply With Quote
Old 05-20-2015, 12:41 PM   #9
1 Rivet Member
 
2015 23' International
Jupiter , Florida
Join Date: Sep 2014
Posts: 9
Quote:
Originally Posted by Skater View Post
Yeah, this is the answer. The charge line doesn't contribute much, while the fridge draws quite a bit on electric mode, plus losses in the inverter. I've done it, but even with 3 batteries and a large solar system, my batteries were pretty run down by the time we got to the site, and we only did it for a few hours. (We were going through a tunnel where we had to shut off the propane, and it was a blazing hot day, so I tried that solution.)
How big is your inverter? I have a 345 watt fridge, a 2000 watt inverter, 2 100 watt solar panels and 2 deep cycle batteries. Am I wrong in thinking this would work while driving? Thank you for any information. This is my first time posting and I have had my AS since November. Loving it!!
__________________
whippet201 is offline   Reply With Quote
Old 05-20-2015, 12:46 PM   #10
2 Rivet Member
 
SKP46015's Avatar
 
Join Date: Apr 2003
Posts: 55
I just run mine on propane going down the road... no muss, no fuss...
__________________
Ed
94 30 Ft. Front Kitchen Excella
99 GMC 2500 6.0L Ext.Cab. 8ft Bed

ARE Shell Topper
SKP46015 is offline   Reply With Quote
Old 05-20-2015, 01:04 PM   #11
Rivet Master
 
AnnArborBob's Avatar
 
2014 27' FB Eddie Bauer
Chelsea , Michigan
Join Date: May 2010
Posts: 1,763
Images: 12
Be aware that regardless of your battery or solar capacity, power via umbilical to the tow vehicle and the power draw of the fridge, the standard Airstream supplied inverter is not wired to provide 110 AC to the fridge, only to three or four designated "inverter outlets." If you want to run your fridge off the batteries and inverter while underway, you will need to change the factory setup to provide inverter power to the fridge 110 AC outlet which is located behind the access panel on the outside of the trailer.

We run the fridge on propane while underway and have never had a problem or the impression that it drains the propane tanks quickly. We are on the road all the time and only fill the propane tanks once or twice during the summer (more in the winter.)
__________________
Bob Martel
WBCCI# 5766
AnnArborBob is offline   Reply With Quote
Old 05-20-2015, 01:24 PM   #12
Rivet Master
 
1974 Argosy 20
2014 20' Flying Cloud
Kooskia , Idaho
Join Date: Jul 2009
Posts: 4,591
Quote:
Originally Posted by dames7 View Post
Can someone tell me how much propane will I use to run the frig. on a 8 hour drive, I have a 2015 25ft Flying Cloud.
As I recall, the propane burner in most RV refrigerators of moderate size use is about 1200 btu per hour. There are 90,000 btu in a gal. of propane, so running full flame about 75 hours per gal. With some on and off, longer, but probably not twice the time. So, 75 to 150 hours per gal of propane.

So, with your 8 hour drive question, maybe 1/10 gal max.
__________________
idroba is offline   Reply With Quote
Old 05-20-2015, 02:15 PM   #13
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 dames7 View Post
Can someone tell me how much propane will I use to run the frig. on a 8 hour drive, I have a 2015 25ft Flying Cloud.
A typical larger fridge like that uses about 1/3 gallon of propane per day if the burner runs continuously.

The burners are about 1000 BTU/H. 81,000 BTU/H = 1 gallon, 81 hours = 1 gallon, about 1/3 gallon per day.

Smaller fridge or conditions allowing the burner to shut off some of the time will reduce the propane draw.

As noted upthread, the propane use by the fridge is negligible while traveling and camping. In nearly all cases the propane used by the water heater will be much greater. The propane use by the fridge only becomes a factor when deciding whether to leave the fridge running while in storage.
__________________
To learn to see below the surface, you must adjust your altitude
Jammer is offline   Reply With Quote
Old 05-20-2015, 02:36 PM   #14
Rivet Master
 
Skater's Avatar
 
1995 30' Excella
Bowie , Maryland
Join Date: Apr 2005
Posts: 2,344
Quote:
Originally Posted by whippet201 View Post
How big is your inverter? I have a 345 watt fridge, a 2000 watt inverter, 2 100 watt solar panels and 2 deep cycle batteries. Am I wrong in thinking this would work while driving? Thank you for any information. This is my first time posting and I have had my AS since November. Loving it!!
The inverter in ours is 1500 watts, so it's large enough to run everything but the A/C in the camper. But, it was installed after the camper was built, so it does attempt to power everything in the camper, if I let it. The factory ones will, as someone noted, only power certain outlets. That all depends on the wiring.

But that's not the issue we're explaining: A 345 watt fridge + 200 watts of solar (under optimum conditions, remember) still means your battery bank is going to be loaded with a 12 amp draw (145 watts/12 volts), plus inverter overhead, so your batteries won't hold out for more than a few hours (exact time depends on the capacity and age of your batteries, as well as the amount of sun your panels receive). For comparison...actually, I'm not sure anything on the 12 volt side draws that much current.

So, sure, you can do it, but not for very long, unless you do the charge line mod that wrhjr3 described, for example, but that will need to be able to supply about 30 amps of 12 volt power if you want the batteries to stay even. (30 amps + long run means some very heavy wire and a very good connector...and can your alternator support an additional 30 amp load? So that could turn into an expensive modification.) And if don't do the full 30 amp setup, and you run longer than expected, say, because of a traffic jam, then you run the risk of destroying your batteries by discharging them too much.

Meanwhile, you probably already carry around something that will power it for weeks without worry... propane. The only downside - against all of what I listed above - is that a few tunnels I've been in require you to turn it off. No big deal; stop, turn it off, then restart it after the tunnel at your next break - it'll be fine for a few hours.

Or just shut the fridge off entirely. Ours stays plenty cold throughout the day on all but the hottest days.

Edit: On re-read, I see wrhjr3 was describing a 3-way fridge. Had one in my B190, but I haven't seen one in any kind of modern trailer. So you'd have to replace the fridge to accomplish that solution.
__________________

__________________
1995 Airstream Classic 30' Excella 1000
2014 Ram 2500 Crew Cab with Cummins 6.7L Diesel

Sold but not forgotten: 1991 Airstream B190
Sold: 2006 F-250 6.0L Powerstroke Supercab
Skater 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


Similar Threads
Thread Thread Starter Forum Replies Last Post
DC to AC inverter for fridge while driving the ponz Refrigerators 20 03-14-2015 05:35 PM
inverter to power fridge while driving? duggie Batteries, Univolts, Converters & Inverters 39 01-24-2015 06:28 PM
A/C switch for dash, run genset while driving? Bella123 Electrical - Systems, Generators, Batteries & Solar 4 09-17-2014 10:17 PM
Inverter to run refer while driving... lilynhoward Batteries, Univolts, Converters & Inverters 26 11-21-2010 03:06 PM
Fridge While Driving Chaplain Kent General Motorhome Topics 18 08-22-2005 01:29 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 07:27 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.