Electrical Fridge wiring

[Billrw136]

I want to put a dedicated connection to the fridge from my tow vehicle via Anderson plugs. I already have a 12 volt outlet from battery to plug at rear of car.
Can anyone help me interpret the wiring at the fridge? The 240 volt connection is clear, but what about the other wires?
Please see photos....

 

[mikerezny]

Hi,
it will help to get assistance if you can provide the make and model number of the fridge. Have you had a look in the manual. It will usually have a clear diagram and instructions on how to wire up the fridge.

My first guess is that it is an AES fridge, meaning it needs TWO sources of 12V: One heavy duty source to power the heater to make the fridge work from 12V instead of gas or 240V; the other is to power the fridge electronics.

Also the two thick red and white wires are most likely the ones that go power the fridge. They probably go to pins 9 and 10 of the 12-pin trailer plug. If that is the case, then you just need to disconnect them from the 12-pin plug and connect them to your Anderson plug.

I hope this helps.

cheers
Mike

 

[Drover]

Doesn't look like a Domestic set up Bill, take a pic of that diagram with the hazard symbol it may give clues.
Since either Red or White can be 12v Pos on vans a meter to test polarity is advised unless you find a circuit diagram.

 

[Billrw136]

Thanks @mikerezny and @Drover - yes, when all else fails read the instructions. See below for fridge type and wiring.

 

[Billrw136]

The van is a new Starcraft 20ft delivered at end of last year. We have done one trip in it - out west - fridge worked well when in camp, but did not hold temp when driving and running off tow vehicle.
Heading south at Easter and hope to sort it before then.
By the way @Drover if you are ever heading through Gosford give me a shout - room for BigMal out the front! @chartrock has proven this!
Bill

 

[Billrw136]

Not sure why the photos display twice - any ideas folks?

 

[Drover]

Thanks for the invite Bill . I will have a look at the pics on a bigger screen tonight, leave Toowoomba for Texas today, when the sun warms up......
My fridge has a direct run from tug with 6 B&S cable thick as a little pinky and it doesn't do very much on a hot day travelling.....Easter at Bungendore for me.

 

[Billrw136]

Interesting - checked that the fridge connection on the socket on the car was getting power - all OK.
Then checked connection on van and found the connection needed tightening - about 4 turns of the screw. Maybe that will make a difference??
Time will tell...

 

[mikerezny]

Interesting - checked that the fridge connection on the socket on the car was getting power - all OK.
Then checked connection on van and found the connection needed tightening - about 4 turns of the screw. Maybe that will make a difference??
Time will tell...

Hi,
that is good progress. You have probably found it just in time to avoid a melted plug and socket.

It would be quite worthwhile to get hold of a multi-meter and check some voltages. With the van hooked up, engine running, and fridge set to 12V, take three voltage measurements:
1: car battery terminals
2: fridge terminals on the 12-pin plug or socket
3: the thick white and red wires on the plug at the back of the fridge.

If you want the fridge to work at its best on 12V, the difference in voltage between the fridge and car battery should be less than 1V.
If it is more than this, then the voltage you measured at the 12-pin plug will give you an indication of whether the van or tug wiring needs to be larger.

cheers
Mike

 

[Drover]

I have had a look at your pics in big size and some other stuff @Billrw136 , I would say as per the pic below that the red/black wires on the left are your 12v supply and the red/whire wires are the fridge side, the fuse should be on the red wire, you will notice an orange wire this is the wire that tells the circuit board that you are hooked up to the tug........what I would do is check the terminals, that red supply looks a bit dodgy and see how it runs now that you have fixed the loose connection.....If you want to run a dedicated line then you would run it from the tug and replace the red/black connection, cut off the open ends of the original red/black wires and insulate, keep the 12v connection active in your 12pin plug then you won't have to move the orange wire also other things can piggy back this supply like breaksafe etc, so insulating the ends at the fridge will keep things working, adding a fridge switch will stop it from sucking your tug battery dry unless you already have similar fitted...............Of course run a meter over everything to make sure alll is good.

.

 

[Billrw136]

Thanks @mikerezny and @Drover for your replies. Plan is to slow down with the GF and turn my attention again to the van as we head away in about a week. Since my last post - have done fencing, nearly sorted storm water (120 metre run), installed range hood, further bathroom work, general tidying up...
Will let you know what I find with the van after following your suggestions.
Bill

 

[Billrw136]

Hi,
that is good progress. You have probably found it just in time to avoid a melted plug and socket.

It would be quite worthwhile to get hold of a multi-meter and check some voltages. With the van hooked up, engine running, and fridge set to 12V, take three voltage measurements:
1: car battery terminals
2: fridge terminals on the 12-pin plug or socket
3: the thick white and red wires on the plug at the back of the fridge.

If you want the fridge to work at its best on 12V, the difference in voltage between the fridge and car battery should be less than 1V.
If it is more than this, then the voltage you measured at the 12-pin plug will give you an indication of whether the van or tug wiring needs to be larger.

cheers
Mike

Well I have checked voltages - 13.99 at the battery, 13.89 at the plug, 12.38 at the fridge - a drop of 1.5 volts from plug to fridge. The van is the culprit...

 

[Drover]

The 12v from the tug at the 12pin may also run to the battery via the setec or whatever is in your rig, hopefully not via a Jayco birdnest which could account for the voltage drop........running a seperate 12v via anderson to fridge would sort that out but leave the 12v running thru the 12pin just disconnect it at the fridge then everything else will run.................................hang on I said that before I think....no matter.

 

[Billrw136]

Yes - new connection is being planned - cable ordered...

 

[Billrw136]

New wire has arrived. I managed to insert it it through the A frame next to the existing wires. @Drover , @mikerezny and anyone else who would care to comment - do I need to place a fuse in the new wire - the supply in the car already has a circuit breaker fitted...

 

[Drover]

I fitted a 30 amp fuse at the fridge end Bill, I used a reset fuse but one of the big blade fuses will do but the one that can carry the current are about $20 with the fuse at about $5, I used one on my new battery set up.


This the type I fitted................

The blade type comes with 8 B&S cable .......bigger than a match box.........

 

[mikerezny]

New wire has arrived. I managed to insert it it through the A frame next to the existing wires. @Drover , @mikerezny and anyone else who would care to comment - do I need to place a fuse in the new wire - the supply in the car already has a circuit breaker fitted...

Hi,
the correct place to insert a fuse or circuit breaker is as close to the supply as possible. Since you have a circuit breaker fitted in the tug there is no need to add any extra fuses or circuit breakers. More fuses, more circuit breakers, more terminals, etc results in more voltage drop and more places for something to wriggle loose or go wrong.

cheers
Mike

 

[Billrw136]

Thanks Mike and Drover for your replies - much appreciated.
If the rain clears for an hour or so today I will be under the van threading the new cable through to the fridge - drilled holes yesterday to get the cable through the floor to the fridge. Off to Bunnings at 6am to get some Sikaflex to seal the holes. 48 hours till we leave.

 

[Drover]

I have a fuse at either end, having had a similar cable run short out and melt once and the fuse stayed good until the damage was done.... Never did work out why.