Operating a 3-way fridge while driving?

[Tom_T]

Originally Posted by SusanP

*Now Edited*! Looking for hive-mind wisdom about how to keep a newly installed Dometic 2354 3-way pre-cooled fridge cool while driving. We have a 7-pin connection to the trailer, and are towing with a 2016 Hyundai Santa Fe Turbo (can tow 3,500 lbs), and which has a mysterious 'towing package' (?). We have solar panel on the roof, and a 100 lithium ion battery. I've read (a) conflicting advice on keeping the propane on while driving; (b) diverse opinions about whether or not the battery can operate the fridge while driving; and (c) debate over whether or not the alternator keeps the fridge powered. Help! Anybody expert enough to settle this discussion? I've got a 4,000 KM trip coming up soon, and need to know! TIA.

Geez people - I don't think Susan was looking for dissertations on draw, amps, wire gauge, etc. She just needs to know what to do with her fridge in transit, and all y'all are way over complicating this.


Susan -

To start with before the trip for best fridge performance - you'll want to pre-chill it on 120v house hook-up for 24 hours before putting in any food (same as for your home fridge), and then keep it hooked-up & on 120v until ready to leave (also unhook last thing when leaving campsites).

Dometic makes their fridges for trailers & RVs/Class B's to run off of the typical car/truck/suv battery & alternator while in transit, and for short periods of typical meal &/or fuel breaks without depleting the batteries, as does Norcold & the other 2-way & 3-way RV Fridge makers. However, you don't want to leave it on 12v overnight, nor to go on that day-long hike - but switch to Propane then.

It should not run your battery dead for the drive with the engine running at road speeds (but not for idling extended period), with short fuel & meal stops - unless your battery is old or has a problem, or is undersized for your Santa Fe in the first place (some shops will install smaller amp batteries & charge full price for the correct amp battery ). So have the battery checked before the trip(s), along with tires, lights & other "Safety Check" items.

Also, the 4-pin & 7-pin connectors & wiring harnesses in both the tow vehicles and trailers are required to be of the proper gauge to run such RV appliances & recharge the trailer's battery - as well as trailer lights & electric brakes - plus those & all other systems in the tow vehicle by law/code/UL. You would only need to check the wiring for cuts & breaks - as well as if any work, modifications, home-hack-jobs, etc. were done on either trailer &/or tow vehicle.

FYI - I'm also of the school to run them on LP on the road, because it keeps the fridge colder & you don't have to switch until you get to a campsite with 120v hook-ups, which you do want to use in order to preserve your LP. However, there are also certain tunnels nationally which prohibit any propane tanks in them (whether LP appliances are on or off), so you need to plan your routes accordingly regardless of whether your fridge in on 12v or LP.

Also FYI - although I don't know the specific specs on Hyundai's Santa Fe towing option package - but the typical factory tow options for all makes & models usually include heavier duty springs & shocks, better engine cooling with a larger capacity radiator, plus transfer case (with 4WD), engine oil & transmission/transaxle coolers, and the wiring harnesses &/or trailer electrical hook-up (4pin &/or 7pin), hitch receiver, & sometimes a bigger alternator (nowadays they're already high capacity alternators due to all the ECM electronics to run the engine, & the vehicle's various comfort, power & entertainment options).

I've been doing this 3-way fridge thing since I was a teen in our family truck camper & for our towed boat starting in the mid-1960s, and have been doing so with the 2.5 cf Dometic fridge in our own 1988 VW Westfalia since new, and with the 4.5 cf Norcold in our restored 1960 Avion T20 (with electric brakes) since we got it in 2012 & as did the prior owners from 2007-12. So I'm no newbie to this subject.

While our 1970 Puck has an Icebox & no fridge, we have a couple of vintage trailer buddies with 1970s Trilliums who also do run either 12v &/or LP while driving.

So for your 4000 KM trip, you can drive with either 12v or LP (check local, Provincial, State regs on the LP though), and switch to either 120v or LP for long stops & overnight for both best cooling and to conserve LP on 120v whenever & wherever possible.

Hopefully this helps with your Trillium. Have fun & safe travels!

Cheers!

Tom
///////

[Grandfatherjim]

Your lithium battery has different charging requirements than the lead acid battery in the tow vehicle. The alternator is designed to charge a lead acid battery, and will will not charge the lithium battery fully, and possibly resulting in a shorter lifespan.
To deal with this, you need a DC- DC converter, which will increase the voltage in the TV to that required by the lithium.
Meanwhile, to charge your lithium house battery the solar panels require a charge controller that can be set to charge lithium batteries.
If you already have the charge controller, then you will only need the DC to DC converter.
If you have neither, there are units that combine both functions so you'll only need to buy one box.
Renogy is an example of a company that makes these.
Once these are set up, you'll be good to travel with your fridge on DC.

[Grant J.]

Hi Susan we have a 2014 Hyundai Sante Fe Turbo with a 7 pin trailer package and tow a 17ft Boler we had a new 3 way fridge installed 3 years ago (Norcold)and always travel with the 12v on we make sure that before we start our road trip that the fridge has been on for at least 24 hours and is nice and cold before switching it over to 12v.We have had no problems with it our RV tec put a small computer fan in the back of the fridge (not in the fridge but on the outside behind the outside grill) which we can turn on when the weather gets really hot and it really helps with air flow.

[GpaNed]

Hi Susan P, I have been Scamping for 4 years and stopped using the Fridge 12V option after having problems with my vehicle not starting. The normal 7-Pin plug connects your vehicle battery to the camper battery and the Fridge can (and will) drain both. I would unplug my camper at stops and then forget to plug it back in resulting in no camper lights - big safety issue.



I just discovered and installed a "Dual Battery Isolator Relay". This small unit connects the camper battery to my vehicle 12V system only when the vehicle is running. Low cost and easy to install. Now I will use the Fridge on 12V when traveling.


There are many Isolators to choose from but here is the one I purchased.


https://www.amazon.com/Dual-Battery-...08JYQHTRZ?th=1

[bigangelman]

With today's vehicle with all this electric and computerized components, the systems on most car are at their limits. Some vehicles are more sensitive than others also. Just a small drop in voltage can keep your vehicle from starting. These new ones also are much more sensitive on being jump started.
This is why charging while driving is something I won't do. If you must have a heavy duty alternator or a separate one installed. It might save some troubles on the road.

[THene1713]

Originally Posted by SusanP

*Now Edited*! Looking for hive-mind wisdom about how to keep a newly installed Dometic 2354 3-way pre-cooled fridge cool while driving. We have a 7-pin connection to the trailer, and are towing with a 2016 Hyundai Santa Fe Turbo (can tow 3,500 lbs), and which has a mysterious 'towing package' (?). We have solar panel on the roof, and a 100 lithium ion battery. I've read (a) conflicting advice on keeping the propane on while driving; (b) diverse opinions about whether or not the battery can operate the fridge while driving; and (c) debate over whether or not the alternator keeps the fridge powered. Help! Anybody expert enough to settle this discussion? I've got a 4,000 KM trip coming up soon, and need to know! TIA.

1) IF THE 7-PIN is properly wired, so that B+ LINE is active when IGN=ON, 2) and the Trailer and Refrig are properly wired, the Tow Vehicle will power Refrig while driving; 3) the Propane can take over (when/if needed by temperature) when IGN=OFF, and you can TEST/VERIFY PROPER VOLTAGES/ PROPER LPG OPERATION in your driveway. I believe the 12v element is in neighborhood of 200-250-watts, so probably 18-22-amps, 25a Fuses? #10-wire= Best? Possibly #12?

[Darrell in Al]

GpaNed
I've had that happen a time. My lesson learned is to disconnect my 7pin trailer connector if stopped for over a few hours or more. That's with my LJ as my tow vehicle, running it will keep up.
Back on topic:
My Scamp fridge is 120 or propane though. I have towed it with it running on propane but with that I didn't refuel, take a ferry or pass though a tunnel.
Now the stupid stuff we all see at gas stations smoking, yakking on phone, getting back in vehicles and one of the worst leaving the pump running with out watching it or driving off with out removing the pump nozzle. The latter one has been bad... I've seen a "shut off disconnect" not shut off gas everywhere running full tilt.
Now a "my bad habit" not removing my metal fuel cans from my Jeep's fuel can rack(s) to refuel but they are metal on metal same as the fuel tank. I always keep fuel nozzle in contact with can when filling them. If a plastic fuel cans I don't chance it trying to fill on vehicle.
When I was in school (1980's) a classmate of mine found out that Diesel fumes can "explode or flash ignite.

[John in Santa Cruz]

simple test is to plug one of those 12V battery monitor/meters into a cigar outlet on the trailer, unplug the AC and switch the fridge to DC just before leaving, and drive a couple hours, and with the engine still running at a stop, check the system voltage in the trailer. if it is staying over 13V, you have enough current from your tow vehicle. if its dropping well below 12.6V, you probably don't, and if its gotten down to 12.1V, switch that fridge to propane for the rest of the drive.

My Tacoma's factory trailer wiring couldn't handle the little 3-way fridge in my Casita 16. I never bothered to try my Escape's large fridge with my F250's factory tow wiring, I just ran it on propane all the time I didn't have 120VAC.

I'm planning on switching to a compressor fridge once I sort it all out, and upgrading to 200AH or more Lithium, and 300W solar (currently have 220AH of golf cart batts and 160W solar).

[Grandfatherjim]

A compressor fridge really is a treat. We put a small one (1.7 cu. ft or 51 litres IIRC) in our VW and it draws 35 watts, and takes about ten minutes on startup to get down to temp.
With a 105 AH lead acid house battery and 125 watts of solar, we can keep the fridge going more or less indefinitely, assuming of course we get at least some sun. The house battery also gets charged by the alternator so we really are only at risk if we park for many days with no 120 with little sun available.
In general, reducing consumption reducues lots of other issues (don't require as large a house battery, thus don't require as many watts worth of solar, etc), but a new fridge isn't cheap. On the other hand, you may spend as much upgrading everything else, especially if you go to lithium batteries.... something to think about.

[Alex T]

We have a 1973 trillium with original dometic 3-way fridge (Rated 95 watts but currently uses 123-124W on 120V AC) and tow with a 2012 4Runner (all have factory tow package). When using fridge on 12v while towing, we’ve found that, for whatever reason (insufficient alternator? Low gage wiring to the 7-pin? Old TV battery?) the TV cannot keep up with the 12v power used by the fridge, so after 5-8 hours of driving, our brand new 100AH trailer battery was down to 50-60% (in a heat wave). As an earlier poster said, we use ice packs and plan to do 2 hours on, 2 hours off, when driving and using 12v. And we always pre-cool on 110V AC when possible. That’s worked well so far, as we do not plan to use LP while driving for a variety of reasons.

[Steve Outlaw]

Originally Posted by parmm

Yes, you can call it anecdotal, but when you've seen the stupid things people do at gas pumps that I have seen, you would be screaming caution too! Gas stations are a accident waiting to happen in my experience! And yes, I have seen gas stations burn up because of stupidity!

The following quotes are taken directly from the article in the link you provided.


"One hundred seventy-six reports (first-hand and NHTSA’s VOQs) have been received from 39 states and Washington, D.C. In all the reports we were able to verify that no open flames, running motors, or electrical continuity problems were involved."


".... Although the author of this report is not an expert on static electricity. It does appear to many people in the industry, however, that electrostatic charging was the probable cause of the fires."

".... Americans pump gasoline into their cars between 11 and 12 billion times a year without incident."

[Raspy]

Originally Posted by Steve Outlaw

The following quotes are taken directly from the article in the link you provided.


"One hundred seventy-six reports (first-hand and NHTSA’s VOQs) have been received from 39 states and Washington, D.C. In all the reports we were able to verify that no open flames, running motors, or electrical continuity problems were involved."


".... Although the author of this report is not an expert on static electricity. It does appear to many people in the industry, however, that electrostatic charging was the probable cause of the fires."

".... Americans pump gasoline into their cars between 11 and 12 billion times a year without incident."

To be more specific, in that report, 87 of the incidents occurred when the driver got back in the car while fueling, and then returned to the nozzle and touched it. The driver had a static charge from sliding on the car seat. 52 other incidents occurred when the fire started in or at the vehicle fill pipe, apparently from a static charge of unknown origin.

I don't understand how one can make a case that the fridge is dangerous, by citing a report that clearly documents another source for all of the fires discussed in the report.

Not saying the fridge should be left on, but where is the evidence that it has been a problem? And in my case, the fridge is 25 feet or so back from the gas fill on the truck. The trailer is normally sticking out and partially in the way of passing vehicles as I fuel the truck, not right next to another pump.

Clearly, when fueling, it is far more dangerous to get back in the car, and then return to the fuel nozzle, than it is to leave the fridge on. A spark from a finger to the nozzle is much closer to fumes than the fridge burner that is 25 feet away. Bottom line: don't get back in the car while fueling, to wait for it to fill up.

[Keith2000]

Originally Posted by Raspy

Clearly, when fueling, it is far more dangerous to get back in the car, and then return to the fuel nozzle, than it is to leave the fridge on. A spark from a finger to the nozzle is much closer to fumes than the fridge burner that is 25 feet away. Bottom line: don't get back in the car while fueling, to wait for it to fill up.

So maybe I shouldn’t get the bigger gas tank if it takes so long to fill that I’m tempted to get back in my car. So many decisions.

[Darwin Maring]

When in doubt - error on the SAFE Side.
Better SAFE than sorry.

ME, I do not feel comfortable fueling a vehicle with a flame nearby.
ME, I follow the guidelines and do not get back in the vehicle while it is fueling up.
ME, I SAFELY discharge static electricity while fueling.

[FloridaNativeMike]

Originally Posted by Keith2000

So maybe I shouldn’t get the bigger gas tank if it takes so long to fill that I’m tempted to get back in my car. So many decisions.

If you do get back in the car, which I highly advise NOT doing... when you get back out, make sure to touch the body of the car with exposed skin WELL AWAY from the fuel filler to statically discharge yourself away from fuel fumes.

-Mike

[Perryb67]

Originally Posted by Darwin Maring

When in doubt - error on the SAFE Side.
Better SAFE than sorry.

ME, I do not feel comfortable fueling a vehicle with a flame nearby.
ME, I follow the guidelines and do not get back in the vehicle while it is fueling up.
ME, I SAFELY discharge static electricity while fueling.

That's nice and works for you, but I don't buy into that line of thinking.

Everything we do is a calculated risk. Everything! A classmate's sister was run over crossing the street. Do I quit crossing the street? OTOH, in my 20's I buried five friends/acquaintances who died in motorcycle accidents. I chose to not own or ride a motorcycle. It was my choice, but I don't try to guilt others. Safety is relative, not absolute.

This thread has become:

Enjoy,

Perry

[ThomasC]

Originally Posted by Perryb67

That's nice and works for you, but I don't buy into that line of thinking.

Everything we do is a calculated risk. Everything! A classmate's sister was run over crossing the street. Do I quit crossing the street? OTOH, in my 20's I buried five friends/acquaintances who died in motorcycle accidents. I chose to not own or ride a motorcycle. It was my choice, but I don't try to guilt others. Safety is relative, not absolute.

This thread has become:

Enjoy,

Perry

Thanks I was thinking of making a similar comment days ago.

[Darwin Maring]

Originally Posted by Perryb67

That's nice and works for you, but I don't buy into that line of thinking.

Everything we do is a calculated risk. Everything! A classmate's sister was run over crossing the street. Do I quit crossing the street? OTOH, in my 20's I buried five friends/acquaintances who died in motorcycle accidents. I chose to not own or ride a motorcycle. It was my choice, but I don't try to guilt others. Safety is relative, not absolute.

This thread has become:

Enjoy,

Perry

When the sign at the Pump clearly states to Not get into your vehicle while fueling and to dispute static electricity before touching the dispenser why on earth would anyone think they are so entitled to do what ever they think is OK and not follow the safety directions. So much bad advice on this site.

[Glenn Baglo]

Originally Posted by Darwin Maring

So much bad advice on this site.

Is that advice that you disagree with or advice that reputable sources (IE. Motor Vehicle Act ) contradict?

[Darwin Maring]

Originally Posted by Glenn Baglo

Is that advice that you disagree with or advice that reputable sources (IE. Motor Vehicle Act ) contradict?

I just follow the Safety Guidelines that are posted.
I’m thinking different states just might have different guidelines and/or laws regarding the subject and I like to error on the Safe Side.

At some of the gas stations that I have used I have seen attendants rush to turn off the pump when the posted procedures were violated.

Just sayyyyin