Operating a 3-way fridge while driving?

[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.

[Alex Adams]

Susan, you need to post what kind of Tow Vehicle you have and if it has a factory tow package with an upgraded alternator. That way someone can figure out if the alternator would be enough to power the fridge. In addition, we would need to know the gauge of the wire leading from the battery to the 7-pin connector on your tow vehicle. If it is too small, you won't be able to power the fridge. The only legal restrictions I have seen is some bridges and tunnels may require you to turn off the propane before entering. I refuse to get dragged into the debate over having the propane on while driving. You are correct that the inhouse battery cannot power the 12 volt side of the fridge unless you have enough solar mounted to the roof of the trailer.

[AC0GV]

Originally Posted by SusanP

Looking for hive-mind wisdom about how to keep a newly installed Dometic 2354 3-way fridge cool while driving. We have a 7-pin connection to the trailer. 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.

My f150 has a regulated 12 VDC in the 7 pin and will not keep up with the 2 way refrigerator in my Scamp. Scamp says never to drive with the LP tanks on. Refrigerators in RVs take HOURS to cool down. SO I do run mine on gas as I travel, and always stop away from the gas pumps and turn off the refrigerator b4 filling the f150. (Some other locations forbid having the LP gas on also.)

[Glenn Baglo]

Originally Posted by AC0GV

(Some other locations forbid having the LP gas on also.)

Find one (other than tunnels and ferries ) and post it please. From Motor Vehicle Act, not from some forum.

[Borden]

Like Alex we have factory tow package, alternator, electric brakes, hitch, full size spare.

We use 12v for travel between sites and propane or 110v at site.

The 12v uses a lot of battery power and is only viable during travel. We first get things cold with propane or 110v and switch when we leave to 12v.

110v with inverter not possible with our original setup type and propane will blow out during travel.

Sure the above will be the same.

[Lynn Eberhardt]

Some people run on propane, some don't. There are safety concerns. Mine blows out.

A Dometic 2354 draws 175 watts while operating on electricity. That's almost 15 amps at 12 volts. Your car alternator can keep up. Your car-trailer wiring may not, but with the addition of your solar installation, your system may. The only way to know for sure is with a volt meter

Check your trailer battery voltage (with a meter) with the fridge and car running. If the voltage stays at 12.6 or above, you're keeping up. If your system doesn't keep up, remember that a filled cold fridge will stay cold for a few hours. Ice packs in the freezer can lengthen the time. For longer trips, run the fridge two hours on - two hours off. Check your voltage again when you arrive to see if that works.

Have fun on your trip.

[CarlD]

There are two ways to overcome voltage drops originating from the alternator changing charging modes and IR loss in the wire. Run a dedicated 8 or 10 awg wire from the engine compartment to a connector at the rear of the TV and continue the circuit directly to the battery. Alternatively, you can install a DC-DC battery charger, which overcomes the voltage drop in the wires. I would recommend that you also install a dedicated 10 awg wire circuit from the engine compartment to the battery as described above, if using this solution.

In both of these solutions you should add a relay to turn the circuit off if the vehicle is turned off to avoid inadvertent discharge of the TV. The relay coil could be connected to the 7 pin connector power wire if it turns off when the TV is turned off. This is what I have in my truck.

[parmm]

Originally Posted by Glenn Baglo

Find one (other than tunnels and ferries ) and post it please. From Motor Vehicle Act, not from some forum.

You are required to turn off your propane tank before pulling up to fuel pumps at a gas station as your propane refrigerator has a open flame. A pilot light is considered a open flame. You must turn the fridge off before pulling up to the pumps!!! 29 Code of Federal Regulations § 1917.156 (4) Smoking and open flames shall be prohibited in areas used for fueling, fuel storage or enclosed storage of equipment containing fuel. Most states have the same law!



And have there been any fires at fuel pumps? Try this link: http://www.pei.org/sites/default/fil..._incidents.pdf


How do I know? I'm retired from the petroleum transportation business and held a federal Hazmat Certification.

[Glenn Baglo]

But, there are no regulations requiring that your propane fridge be turned off, except for gas pumps, tunnels and ferries. IE. you can drive with propane fridge on.

[CarlD]

You can drive while running your fridge on propane IF you can keep it lit! A 12 volt feed will not blow out!

[gordon2]

Originally Posted by CarlD

You can drive while running your fridge on propane IF you can keep it lit! A 12 volt feed will not blow out!

From what I have experienced and what I have read... a fridge on the port side is prone to have the flame blow out from passing vehicles, especially if both intake and exhaust vents are side mounted. But one on the passenger (starboard) side is usually not a problem. Mine is on the starboard side with a roof exhaust vent and it has worked perfectly on propane when traveling.

But if you have a three way fridge that will run on 12 volts DC then that is a better option. And you can usually make that work with three way absorption fridges by upgrading wiring, battery, and maybe even the tug's alternator.

However some absorption fridges only run on 120 VAC or propane. Mine is one, and while I try to avoid propane use on the road, sometimes it is needed as the fridge really does not hold cold very long in hot weather and there is no 12 VDC heater.

As for shutting it down at gas stations.. thats a given! Sparks at gas pumps is a known threat. But the only fire I am aware of with a fridge running on propane at gas pumps occured when the owner accidently splashed a little gas from the pump into the fridge compartment. And that was a big fire that pretty much destroyed the gas station and totaled the RV. So use common sense.. no open flames near anything combustible!

[John in Michigan]

With our Boler 17, we recently towed with the Dometic RM360 fridge running on propane. The fridge is on the driver's/port side. The lower vent is located high, above the belly band. The fridge ran fine the entire time. This success could be attributed to the vertical sheet metal shield covering the burner area.

Also previously towed the Trillium 4500 a couple of times with the fridge running on propane. Again, no problem. Again, the fridge is located on the port side, but down low, and the burner is completely shielded from drafts.

I am also definitely interested in testing running the Boler 17 fridge on 12vdc power from the 7-pin. I have already verified the the 7-pin 12vdc+ charging pin on the tow vehicle is powered when the vehicle is running. I agree that would be more convenient than propane for gas station stops...

[Perryb67]

Originally Posted by parmm

And have there been any fires at fuel pumps? Try this link: http://www.pei.org/sites/default/fil..._incidents.pdf
.

Read it carefully. It's anecdotal.

Enjoy,

Perry

[John in Michigan]

SusanP, in your setup with solar panel and a 100 ah lithium battery in the trailer, the lithium battery will run the fridge in 12vdc mode (175 watts, approx. 15 amps at 12vdc), but the fridge but will deplete the battery in a few hours without sunshine and/or sufficient supplemental power from the 7-pin 12vdc+ charging pin. To avoid depleting the lithium battery, IMO you should use a multi-meter to measure the voltage and current provided by the tow vehicle charging wire to the fridge (tow vehicle running) with the lithium battery disconnected.

EDIT: Even with lots of sunshine, the solar charge controller won't maintain the initial battery charge level unless you have at least 300 watts of panels.

[parmm]

Originally Posted by Perryb67

Read it carefully. It's anecdotal.

Enjoy,

Perry

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!

[Raz]

Yup

[Glenn Baglo]

Originally Posted by Raz

YupAttachment 142083

Flames appear to be coming out of the open door of the tow vehicle. What was the cause of the fire?

[Borden]

Originally Posted by John in Michigan

SusanP, in your setup with solar panel and a 100 ah lithium battery in the trailer, the lithium battery will run the fridge in 12vdc mode (175 watts, approx. 15 amps at 12vdc), but the fridge but will deplete the battery in a few hours without sunshine and/or sufficient supplemental power from the 7-pin 12vdc+ charging pin. To avoid depleting the lithium battery, IMO you should use a multi-meter to measure the voltage and current provided by the tow vehicle charging wire to the fridge (tow vehicle running) with the lithium battery disconnected.

EDIT: Even with lots of sunshine, the solar charge controller won't maintain the initial battery charge level unless you have at least 300 watts of panels.

Can only say play safe; think 12v is for travel.

[gordon2]

Originally Posted by Glenn Baglo

Flames appear to be coming out of the open door of the tow vehicle. What was the cause of the fire?

As far as I can find.. the cause was never released. There was some talk about engine backfiring before his trip.

https://www.youtube.com/watch?v=XBTuiLX3h4I

Also see:
https://www.ourmidland.com/news/arti...at-6931395.php

And this article also says the cause might not have been related to the propane. It also mentions the case with the fuel spill to the vent that I mentioned.. more follows.

[ehoepner]

When towing my 3 way frig is always on DC. I cool it down on AC at least a day before leaving home. The only issue with using DC while driving is the wiring of the tow vehicle. The wiring on some tow vehicles is not done correctly. They use a 16 or 14 gage wiring instead of a 10 gage wiring for the DC voltage supply to the trailer.

If the tow vehicle wiring is 16 or 14 gage the tow vehicle cannot supply enough volt/amps to the trailer to run the frig.