Run 12v/propane refrig on inverter while driving?

[babock]

Originally Posted by rockfordroo

the door (climate control) heater pulls 0.5 amps

The door heater draws 0.5A of 12V DC...not 120V AC

[rockfordroo]

Originally Posted by babock

The door heater draws 0.5A of 12V DC...not 120V AC

You're correct. I got carried away. Thanks for the correction!

So 2.7amps at 120VAC and 27amps at 12VDC plus inverter losses.'

Original post updated.

[emm-dee]

Way back in the 60’s NASA spent megabucks developing a pen that could be used upside down or in zero gravity.

The Russians used a pencil.

Just saying.

[1953m38a1]

After 5 pages of highly differing opinions, it takes Emm-Dee to sum it up succinctly....Follow the KISS principle....,now where did I put my pencil!

[Windjammingnc]

So, I did what you are wanting to do (short of running new wire in the truck). I will explain why I did it and observations since.


In our case, the fridge would blow the thermal fuse (granted this just started happening during our second year of camping with the new rig) when we traveled with it on gas.. The downside when the thermal fuse goes is it disables all the fridge heating including AC which pretty much creates a useless hole in the wall of the trailer with two doors. After a mobile service person and two dealers (including my own) looked at it (and replaced all 3 blown thermal fuses), I decided that clearly the placement of the fridge was probably creating wind turbulence that would blow out the flame and an abundance of gas before the re-light would occur was creating a flameball that was hot enough to blow the thermal fuse.


Given that we really didn't enjoy rolling the dice and arriving to our destination with an inoperable fridge, I chose a technical workaround. In our case, the Dometic heating element draws 425Watts. On a positive note, the Fridge's AC circuit is also shared with the TV in the living area, the Bathroom receptacles (trying to understand the logic there) and the bedroom receptacles (including TV). This means that by installing an inverter on this circuit will also power the TVs (and Satellite receiver, etc) when we are dry camping. I could replace the Inverter I installed by the TV (which sometimes would blow the 12V fuse).


I purchased a 500W Pure-Sine Inverter (Victron) and a compact Automatic Transfer switch that would allow that circuit to be automatically switched to shore power when trailer was connected ( I realize there are inverters with Builtin Transfer switches).


Now the observations: The inverter draws about 40 Amps when powering the fridge (although this does increase when the battery voltage drops over time). When we first start out on a trip and the truck's battery is getting charged with the alternator at 14.5V, the net draw on the Trailer batteries is about 6-8Amps so the truck is able to provide around 30A of 12V. The problem occurs about an hour into the trip when the alternator drops it's voltage down to 13.6V, then the net draw on the batteries jumps up to 15-18Amps.


After about 4 hours on the road, the battery monitor shows the batteries (pair of 6V Trojans) usually around 75-80% state of charge. We are known sometimes for marathon trips of 8-9 hours which usually doesn't bode well for the batteries, especially if we happen to dry camp at a Cracker Barrel and would start the next day's trip with even more depleted batteries (sometimes we'll run the Honda generator for an hour or so while there).



The option to travel without the fridge on just doesn't work, especially in the summer when temps are in the 80's and 90's since the fridge internal temp will rise into the 50's in a matter of hours and it takes quite a while for the fridge to cool down once turned on again.


What's our solution going forward? We do plan to add solar to the trailer which will help if we are traveling on a sunny day and make up for the difference between truck charge rate and inverter draw.


Sorry for the long post but just wanted to convey my observations on installing an inverter to run the Gas/Electric fridge on AC while traveling.


Happy travels.

[Flapjackdenny]

We have a Dometic AC/LP ref/freezer in our 2015 Sunseeker Sprinter. We are fulltime 15 months and our 3rd Summer since buying this rig. The unit works flawlessly, we drive 4 to 8 hours somedays and have never lost a drop of food or beverages. We dont run our gas either. Seems to be alot of work if you are travelling short periods if you are going longer than I would get a 12 v Yeti plug it in and put thing s in there to lighten the frig load. Also, adding a flex solar panel or two may be a good idea to keep batteries charged as well, solar has come way down as have the Lithium powered battery generators too.

[WolfPup2018]

Pre cooling the fridge or just bringing a cooler for the critical items seems a lot less work coming up with all that wiring and cost. 3/4 of the eatable food don’t even need refrigeration

[RStock]

This is an interesting topic and thread. I'm new to this, so this question may be dumb, but does anyone run a small generator plugged into the RV while travelling to operate the fridge? Assuming that that generator could be bolted down to the trailer tongue and permanent fixed wiring run to the generator location.

[WolfPup2018]

Uh I don’t think a lot of people do that. Running a generator out of the back of a truck or camper while driving down the road. I’ve camped for years w/out a trailer and never had a problem with the good ol cooler. The Lifetime brand cooler at Walmart for $95 holds up to the $500 yeti cooler and thins lifetime cooler kept my food FROZEN for an entire day.

[Sir Nickel's Worth]

This last winter in Arizona we enjoyed doing the laundry using solar power. We were boon-docking. No hookups totally off the grid. Our machine is your typical residential Amana 110V. I have 8 100amp solar panels and 10 6 volt cart batteries (With 6 onboard and 4 wired in separately). The inverter is a GO Power 2000 Watt Pure Sine wave model. I have watched the relay panel from the Morningstar controller. The batteries drop very little also we only do the laundry during the day with the sun shining. I know this is off topic but this winter I plan to purchase a refrigerator. Not a bar frig but something a little bigger in the 100 to 150 watt range. On startup I anticipate a larger than normal power consumption so I will run the generator for that. Once the refrigerator has cooled its power use will not be that great. Also when traveling the onboard refrigerator runs on 110v AC. If you plan on traveling a lot consider Solar Power as the Sun is there, why not use it since it is Free. Any reputable solar dealer will be able to advise you on how big a system you will need.

[RStock]

Yup I thought it was a dumb idea, but i couldn't help but ask. Good tip on the coolers. Thanks WolfPup2018.

[rockfordroo]

Originally Posted by RStock

Yup I thought it was a dumb idea, but i couldn't help but ask. Good tip on the coolers. Thanks WolfPup2018.

I know some motor home people say they do it because the engine driven AC isn't enough to cool the entire MH, so they use their generator to run their rooftop AC. But their generators are "built-in."

[aeblank]

Swampy, in this very thread, said he does run his generator while driving.

I have a generator in the back of my truck stuck at the 5 hours for break-in. Just don't seem to need it. Loving my solar.

[trishas47]

I drive 5,000 miles with propane in refrigerator..

[aeblank]

Originally Posted by trishas47

I drive 5,000 miles with propane in refrigerator..

Me too, except way more miles. Super simple and easy.
But it's not up to us to decide if it's a good idea. It's a cool experiment, IMO.

[chriscowles]

Originally Posted by aeblank

... It's a cool experiment, IMO.

At worst, I'll end up with an AC outlet near the bed of my truck. And that's only if I get past the preliminary test using an extension cord running out the rear window.

[chriscowles]

I'm reviving my old thread. With time on my hands, I'm putting something together for a test.

Originally Posted by Windjammingnc

So, I did what you are wanting to do (short of running new wire in the truck). I will explain why I did it and observations since. ...

... In our case, the Dometic heating element draws 425Watts. On a positive note, the Fridge's AC circuit is also shared with the TV in the living area, the Bathroom receptacles (trying to understand the logic there) and the bedroom receptacles (including TV).

... I purchased a 500W Pure-Sine Inverter (Victron) and a compact Automatic Transfer switch that would allow that circuit to be automatically switched to shore power when trailer was connected ( I realize there are inverters with Builtin Transfer switches).

... Now the observations: ...

@Windjammingnc (if you're still around): I'm unclear as to where you mounted the inverter in question. Was it in the truck, with AC run to the back of the truck? Or in the trailer, with large gauge wire from the truck to the trailer to carry the heavy DC load without loss? Or some other arrangement?

[chewie37]

Our new Surveyor 252RBLE has a small outdoor kitchen with a second refrigerator. And it does energize on 12V alone.

I also know for sure it's a plain old 110V Everchill with the temperature adjustment knob inconveniently located at the outside back of the unit.

How do I know that? Because I pulled it out of the camper and plugged in to an outlet in the garage to figure out which turn direction made it hotter or colder.

Anyhow, that indicates to me that the 110 outlet in the kitchen area of the camper is likely wired in to an inverter somewhere in the coach.

Eh, it's a quiet weekend here - maybe I should go trace that setup out. Might be nice to know how to completely turn it off if we want to.

[chriscowles]

Originally Posted by chewie37

... Might be nice to know how to completely turn it off if we want to.

Independent of my plan to run the inside refrigerator on AC while driving, my outside kitchen refrigerator is a tall dorm type that works on AC only. I'm going to trace the circuit to see what it's linked to. I may want to turn it off when running my small generator for the AC. I'll probably just add toggle switch inline with the power cord, if I do anything at all. I'll confirm the one below is rated for the refrigerator load before I'd use it.

https://www.walmart.com/ip/Leviton-H...witch/23331130

[rockfordroo]

Originally Posted by chriscowles

Independent of my plan to run the inside refrigerator on AC while driving, my outside kitchen refrigerator is a tall dorm type that works on AC only. I'm going to trace the circuit to see what it's linked to. I may want to turn it off when running my small generator for the AC. I'll probably just add toggle switch inline with the power cord, if I do anything at all. I'll confirm the one below is rated for the refrigerator load before I'd use it.

https://www.walmart.com/ip/Leviton-H...witch/23331130

That switch says it's only rated for 3 amps, so the fridge can't use more than 360 watts at 120VAC.

When you find the power usage one your fridge in watts, divide by 120VAC and you'll know how many amps your switch needs to handle.