Fridge setting when towing.

[Banus]

Hi all. Quick easy Q for most of you I'm sure.
I have a 2019 Swift Challenger with a three way Thetford tall fridge (gas, mains and 12v), and the usual Sargent power unit. Can someone please advise how to power my Thetford fridge when towing. So I'm presuming that the Sargent unit has to be left on, (little black button down) and the fridge set to the 12v setting? Correct? Also, is it critical which order things are connected, ie make the above settings before connecting to the car? I understand that it wont get any cooler but the car will just maintain the temperature. Thanks.

 

[donde_ayer]

Fridge on 12v, main van panel set to car (van panel may vary, not sure). Disconnect from mains, connect to car, turn car on. Bare in mind the 12v doesn't chill the fridge, it can only maintain it, so make sure you use mains or gas to bring it down to temperature before the journey.

 

[Andy Norfolk]

We always put the fridge on mains one or two days before travelling. Also we put pre frozen things in the freezer not things that need to freeze.

 

[Buckman]

The car needs tt be wired correctly to take into account a Smart alternator so that it will supply a constant 12v to the fridge while towing.

We always put the fridge on mains one or two days before travelling. Also we put pre frozen things in the freezer not things that need to freeze.

We have the Thetford 8xxx series and no issue with it freezing food.

 

[Andy Norfolk]

The car needs tt be wired correctly to take into account a Smart alternator so that it will supply a constant 12v to the fridge while towing.

We have the Thetford 8xxx series and no issue with it freezing food.

I wasn't suggesting the freezer won't freeze things. The question was about travelling and I find putting pre frozen items in the freezer helps maintain the fridge temperature. I also have a Thetford 8 series fridge freezer.

 

[JRT]

We have found on the 8--- series fridges the manual underestimates the ability of the fridge to keep things frozen. When picking our van up from storage and without it being pre cooled we find it will still keep things frozen after being transported in our cool box and placed in the freezer compartment and then run on 12V.

If starting from home though we always pre cool the fridge on 240v.

 

[Buckman]

We have found on the 8--- series fridges the manual underestimates the ability of the fridge to keep things frozen. When picking our van up from storage and without it being pre cooled we find it will still keep things frozen after being transported in our cool box and placed in the freezer compartment and then run on 12V.

If starting from home though we always pre cool the fridge on 240v.

I think they are just covering their rear ends?

 

[ProfJohnL]

I understand that it wont get any cooler but the car will just maintain the temperature. Thanks.

As buckman alludes, in many cases running a fridge on 12V derived from the tow vehicle (which can only happen when its engine is running) can produce unpredictable cooling performance the fridge manufacturers cannot predict or account for the way the air will move around the fridge whilst traveling. But in practice if a three way fridge is powered on 12V dc the heating element will be almost as effective as using gas or mains electricity. And it will cool the fridge. It just that when travelling the airflows around the fridge are not optimised, and the 12V element may be compromised.

 

[Johnb]

Hi all. Quick easy Q for most of you I'm sure.
I have a 2019 Swift Challenger with a three way Thetford tall fridge (gas, mains and 12v), and the usual Sargent power unit. Can someone please advise how to power my Thetford fridge when towing. So I'm presuming that the Sargent unit has to be left on, (little black button down) and the fridge set to the 12v setting? Correct? Also, is it critical which order things are connected, ie make the above settings before connecting to the car? I understand that it wont get any cooler but the car will just maintain the temperature. Thanks.

If able run the fridge from mains or gas for a period before setting off to cool it down. Advice above regarding pre-frozen stuff etc straightforward.

Before towing:

Have the "power unit" black button down and, in my case set fridge to automatic. I think your fridge will have an automatic setting but if not set to 12v.

When mains power is removed from the van and the gas is shut down prior to towing the fridge has no power and in my case beeps to warn. ( I think your fridge will do the same).

Hitch car to van and connect electrics. The fridge will continue to beep until the engine is started and 12v feed provided for the fridge by the car alternator.

I don't think setting the fridge to automatic (or 12v) after simply connecting to the car will make any difference. As soon as the car is started it will provide 12v and the fridge will operate as expected.

Other fridges may operate differently and hopefully someone will explain their operation but I'm pretty sure your fridge will work as I've described.

 

[Banus]

Many thanks for all of the above advice and tips which I completly agree with and understand the logic. Unfortunately, we can't precool our fridge as its in storeage, so at present we take our cold items in a insulated cold bag with ice blocks to our van and leave them in the car until we arrive at our site where we transfer them into the fridge. The bag works really well and the items are still as cold as when we took them out of the fridge at home. On arrival at our camp site I then run the fridge on EHU and in a very short time the fridge has cooled down.
The reason for starting this thread is that I find it a shame that we have a function on our van / fridge that we weren't using. ie running it from the car when travelling which would be useful if we do longer trips next year on the continent.
Johnb - Thanks for that and that's exactly what I was look for and I'll try your suggestion. It sounds as if our fridges are the same as apart from mains, gas and 12v it also has a auto setting. Thanks all.

 

[Ferrodo]

We don’t use the fridge at all when towing but put whatever cold/frozen foods in a good quality cool box. The reasons being is that we usually do a shop on arrival and also to keep weighty objects from bouncing around on the fridge shelves causing damage. The other annoying thing with 12v operation is that when you stop for a comfort break and turn off your engine then you will have an alarm chirping at you. Unless, of course, you disconnect the towing electrics…. Just remember to reconnect before driving off.
Nope…… cool box is easier and far more reliable….. just our preference.

 

[Buckman]

We don’t use the fridge at all when towing but put whatever cold/frozen foods in a good quality cool box. The reasons being is that we usually do a shop on arrival and also to keep weighty objects from bouncing around on the fridge shelves causing damage. The other annoying thing with 12v operation is that when you stop for a comfort break and turn off your engine then you will have an alarm chirping at you. Unless, of course, you disconnect the towing electrics…. Just remember to reconnect before driving off.
Nope…… cool box is easier and far more reliable….. just our preference.

We do the same. Why lug around stuff that you can buy at your next stop over? Most of our stuff goes into a decent quality cool bag.

BTW no need to disconnect when stopping while the towing. Simply switch off the fridge.

 

[Ferrodo]

We do the same. Why lug around stuff that you can buy at your next stop over? Most of our stuff goes into a decent quality cool bag.

BTW no need to disconnect when stopping while the towing. Simply switch off the fridge.

Yes you are, of course right Mr Buckman. But will you remember to switch it back on again??? Either or. 🤔🤔

 

[Buckman]

Yes you are, of course right Mr Buckman. But will you remember to switch it back on again??? Either or. 🤔🤔

Unlikely to remember, but will you remember to reconnect the car electrics. LOL! We have tried the fridge on 12v, but found it was not very effective however that was before I found out that we had a Smart alternator.

 

[Ferrodo]

The main issue I have with it is that a caravan fridge takes a lot of grunt to power the thing properly. One dickey connection, smart alternator, the wrong gauge wire and a cheap VSR and everything goes west resulting in ( I know this is improper language) warm beer. Too many variables in the equation for me.

 

[Hutch]

We do the same. Why lug around stuff that you can buy at your next stop over? Most of our stuff goes into a decent quality cool bag.

BTW no need to disconnect when stopping while the towing. Simply switch off the fridge.

There should be no need to switch the fridge OFF, that should be automatic, no power to he fridge or battery if the car engine is not running.

 

[Buckman]

There should be no need to switch the fridge OFF, that should be automatic, no power to he fridge or battery if the car engine is not running.

That is what I thought, but I read numerous recommendations to disconnect the electrical cable from the car on ferry crossings to prevent a flat battery?

 

[Ferrodo]

And so that the ATC doesn’t get confused and lock on the brakes.

 

[Hutch]

That is what I thought, but I read numerous recommendations to disconnect the electrical cable from the car on ferry crossings to prevent a flat battery?

I have left the car connected to the van on short crossings, ie, Dover Dunkirk, with no problems, but on a few occasions have disconnected. Obviously the ATC doesn't use much power.

 

[Buckman]

I have left the car connected to the van on short crossings, ie, Dover Dunkirk, with no problems, but on a few occasions have disconnected. Obviously the ATC doesn't use much power.

I have no idea if the power supply to the ATC would be the same to power the fridge?

 

[Ferrodo]

No ATC is permanent live. Fridge is switched.

 

[Banus]

I’ve just returned from the IoW and after switching off and locking the car (XC60) noticed that the green ATC light remained on. Only an hour crossing though and IIRC it was off when we returned to the car deck.

 

[Ferrodo]

I’ve just returned from the IoW and after switching off and locking the car (XC60) noticed that the green ATC light remained on. Only an hour crossing though and IIRC it was off when we returned to the car deck.

Interesting, the ATC feeds off the permanent live so I wonder how it could turn itself off. I assume it switches back on after the car is started?

 

[GUMPY]

I just put the food in the fridge set it to 12v and off we go. When we get on site change it to 230v or gas. Not been a problem and no warm white wine, even with the short five hour journeys we do.

 

[Buckman]

I just put the food in the fridge set it to 12v and off we go. When we get on site change it to 230v or gas. Not been a problem and no warm white wine, even with the short five hour journeys we do.

You are braver than us. If necessary we will travel with only the freezer containing food. All stuff in the fridge part is removed while on the road.