Running a 3 way fridge on 12v

[Wil Senior Member Find all posts View Profile Close Wil]

Does anyone run a 3 way fridge on 12v whilst travelling?

I am running mine using a voltage booster for the alternator, through a redarc isolator, into a ultima yellow top d34 under the bonnet, then 6mm cable to camper into 100ah battery then the fridge draws off this. Is there a better way? Fridge seems very power hungry.

On most trips also running a 40L engel on freeze and a waeco cooler. Havent had the alternator light come on, but reckon i must be close to its comfort zone.

Also, any recommendation for under bonnet aux battery? I am after more storage.

[Guest Close Guest]

3-way fridge is best run on gas, not DC.

[Wil Senior Member Find all posts View Profile Close Wil]

Yes, and as soon as we open up straight onto gas or 240v. But doesnt work using gas when on the move so need to be using 12v

[Borec Senior Member Find all posts View Profile Close Borec]

I have mine running on battery only when driving, it will drain your battery very quickly (only takes couple of hours). As soon as I stop somewhere for longer then couple of hours it runs on gas.

[Guest Close Guest]

Insulate the fridge well if possible
Start with all contents at temp or lower before the trip
Use 6 B&S cabling to the camper to minimise voltage drop
Add solar panels to charge on the go.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Most run a separate line of the cranker to run a three way, via its own isolator (ie an ignition controlled relay) or fridge switch etc. If you have heavy cable from the cranking battery to the isolator and aux, then run 6mm to the fridge its not so bad but not an ideal solution and you still should have some type of isolator for the fridge.

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

Hi Wil and you should never have a 3 way fridge connected to your house batteries or to the cabling that charges the house batteries.

As LeighW posted, you should have a separate power supply for a 3 way fridge and this should be at least 10mm2, running from the cranking battery directly to the 3 way fridge.

Also as LeighW posted, the fridge circuit needs to be isolated when the motor is off and NOT via an ignition ON controlled relay.

If you use a simple ignition ON relay, as soon as you turn the ignition on, the fridge will be powered up as you are trying to start your motor.

Another suggestion, if your fridge is a new 3 way fridge, then it should be “T” rated or TROPICAL rated and as such, it will keep it’s COOL a lot longer with out turning it on.

I have a lot of customers who simply cool their fridge down over night with gas or 240vac and then do their days drive without powering their fridge and even when traveling in northern parts of Australia during summer they have no problems but you must make sure you don’t use the fridge until it’s back on gas or AC.

[Nova Member Find all posts View Profile Close Nova]

When run on 12/240v the fridge basically has a heater to do the same job as the gas flame. You basically have a power hungry resistance heater running off your car battery. Converting electricity into heat isn't very efficient.

Cheers, Nova

[Wil Senior Member Find all posts View Profile Close Wil]

Thanks guys. Ours is an older model from a 2005 jayco wind up so prob not a T model.

It is a pain in the arse when travelling as the control to change from 12v / 240v / gas is on the front of the fridge. So when you want to change you need to crawl in as the fridge is right at the back on the drivers side. Problem is that the floor space is full of stuff when travelling so you need to take half the stuff out just to change the fridge over.