Running Car Battery to Caravan

Submitted: Thursday, May 22, 2008 at 15:24
ThreadID: 57892 Views:7397 Replies:6 FollowUps:0
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Hi to all you very knowledgable people out there. (Grovel Grovel)

Dumb Blonde Chick here!

I'm sure I am going over ground already covered, but can't find the info I need. Perhaps someone would be kind enough to point me in the right direction.

Can I run the existing battery power from my car to a caravan in order to be able to have the caravan fridge running whilst travelling from point A to B - through an Inverter of course (I'm not that dumb :))

I have already purchased a 800W Modified Sine Wave Inverter (but can return if unsuitable)

How does one go about this transformation, if possible.

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Reply By: Member - 120scruiser (NSW) - Thursday, May 22, 2008 at 15:50

Thursday, May 22, 2008 at 15:50
Hi Selena.
In your 7 pin flat trailer wiring plug there will be one wire which is an auxillary. Most people run this one back to the battery through a fuse and then into the caravan wiring. Are you sure the fridge won't run on 12 volts as well as I think it might? I know our old caravan used to have 12 volt lights and all so you could just pull up and not even disconnect from the car if you didn't want to. This would be the best way. The other way would be to run nice thick wire from your battery through a 50 amp anderson plug. Thats what I did in my camper trailer.
Hope this helps.
AnswerID: 305297

Reply By: Member - DAZA (QLD) - Thursday, May 22, 2008 at 15:53

Thursday, May 22, 2008 at 15:53
Hi Selena

Before you set fire to your Vehicle and Caravan, get your local
Auto Electrician, to wire in a Anderson Plug, and check your caravan
wiring, you might have a problem with Insurance if the lot goes up.
some Technical minded people can do it some cant.

AnswerID: 305298

Reply By: Member -Dodger - Thursday, May 22, 2008 at 15:55

Thursday, May 22, 2008 at 15:55
AS most Caravans have a three way fridge Viz. Gas, 240V and 12v then you can run a 12v lead from the car via an anderson plug to the vans 12v system and the fridge 12 connection. This should be done through a 40 amp relay that is only active when the ignition is on. If you are not sure then contact your nearest caravan service person or an auto electrician.
I used to have a handle on life, but it broke.

Cheers Dodg.

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AnswerID: 305299

Reply By: Member - barry F (NSW) - Thursday, May 22, 2008 at 17:10

Thursday, May 22, 2008 at 17:10
Our van has a three way Frig (I thought all vans did?) Anyway, when having our tow bar etc fitted to the vehicle, the Auto electrician simply wired through the flat plug connection that connects clearance lights, blinkers etc. I think it is commonly caller a "hot" wire? Anyway it works.
We had him set it up so as when the vehicle ignition is switched off it cuts the power to the Frig. Apparently Fridges will flatten your vehicle battery very quickly if the frig is left running while you are parked. Hope that helps. Cheers.
AnswerID: 305317

Reply By: SPRINT-GTO - Thursday, May 22, 2008 at 17:30

Thursday, May 22, 2008 at 17:30
As others have advised get your local "sparky" to wire and fit an anderson plug to rear of your tow vehicle. Its not a big job and you should have no worries from there on as fridge in van will be powered whilst your driving. Re the modified Sine Wave inverter I would return it and if you do later decide to wire an inverter into your van only buy a pure wave inverter and not a modified one.

cya Gary
AnswerID: 305322

Reply By: Ircon - Friday, May 23, 2008 at 10:07

Friday, May 23, 2008 at 10:07

If your caravan fridge is a three-way absortion unit, they can draw a fair amount of current and if your wiring is not up to the job you may not actually be getting 12 Volts at the fridge terminals. This is the reason people are suggesting you have an auto electrician upgrade you wiring.
Sometimes it is not practical to use the 50A Anderson plug. A possible alternative is to change to a 12 pin flat connetctor and use the 30 A pins. This connector has auxiliary terminals which can take heavier guge wire.
If you are wiring the caravan fridge from the cars cranking battery you should perhaps think about having an auto electrician install a solenoid operated from the ignition switch or a "smart" separator installed so that the you isolate the fridge from car battery when the car's engine is not running. Pain in the proverbial if you go sight seeing for a couple of hours and when you return you don't have enough charge in the battery to start the car.


AnswerID: 305424

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