Electrical Can I run 2 positive from VSR for 12pin

shmick

New Member
Jan 15, 2020
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Meh-lbourne
#1
Hi all,
I almost picked up my new van yesterday, but Andrews ruined it 12hours before pick up as I was unclear if I was allowed.
Anyway, I figured use the next 6 weeks to wire up the 12pin myself since it seems easy.
Question, I have a VSR running my second battery in boot. Can I run the positive for Pin 9 from the VSR or do I need a new VSR? I don't want to run to battery as we stop often in towns. Not sure if van fridge cuts out automatically (does fridge run thru J35 which has cutout?).
Thank you.
 

mikerezny

Well-Known Member
Sep 11, 2016
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#2
Hi,
we will need to know more about your setup to give you correct advice.

What brand and model fridge do you have?

Just so we are all on the same page.

take care
Mike
 

shmick

New Member
Jan 15, 2020
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Meh-lbourne
#3
Hi,
we will need to know more about your setup to give you correct advice.

What brand and model fridge do you have?

Just so we are all on the same page.

take care
Mike
Hi Mike.
TBH I don't know. But it's a 3 way fridge, 90-95L that comes standard on a Journey Outback.
Michael
 

Drover

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Nov 7, 2013
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#4
A 3 way Fridge on 12v only runs from your tug, it never runs from van battery, if you run your van/fridge 12v from your aux battery then all is good, if you just add a Fridge Switch to the back of your fridge hooked into the 12v feed then you don't have to worry about draining power from any battery as it will shut off soon as you stop..and is a damn sight easier and means whatever vehicle you hook up to it will shut off power.......

Fridge Switch is a units name, about $60 and plug an play, easy peasy.
 

shmick

New Member
Jan 15, 2020
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Meh-lbourne
#5
Ah ok. So essentially acts kind of like a VSR. When it detects voltage drop it cuts out automatically. So if I stop for lunch fridge in van cuts out when car is off.
This would save me from messing around with the VSR since it's kind of fixed in engine bay.
Thanks. I'll check it out.
 

mikerezny

Well-Known Member
Sep 11, 2016
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#7
Hi Mike.
TBH I don't know. But it's a 3 way fridge, 90-95L that comes standard on a Journey Outback.
Michael
I would suggest you ring the dealer to get the brand and model fridge that is installed in your van. Then do an internet search and download the manual for the fridge. Save yourself a lot of wasted time, effort, and confusion.

The reason I ask is that there are two types of three-way fridges: Manual Energy Selection (MRS) and Automatic Energy Selection (AES).
The way they run off 12V is quite different and you need to know the type of fridge you have or you will be lead up the garden path by people who will be giving advice on a fridge that is different to yours.

A MES fridge has a SINGLE set of 12V terminals on the back that connect to the 12V heating element on the fridge via the energy selection switch on the front of the fridge. In Jaycos, these two terminals are wired directly to the 12-pin plug terminals 9 and 10.

An AES fridge is very different. It need THREE sources of 12V to operate.
1: 12V to power the electronics on the fridge. That means the load isolation switch in your van must be on to power the fridge electronics from the van battery.

2: 12V to power the heating element, Note that the element is 175 W which will draw 15A on 12V. The biggest issue with people whinging that current model fridges will only maintain temperature or not work at all on 12V is that they wire run back to the tug battery is too thin and there is insufficient voltage at the fridge to provide the correct amount of power. Search this forum, this had been discussed many times and in great detail.

3: 12V from your tug to let the fridge know that the engine is running and to then switch to 12V and run the 12V heating element. This is called the D+ or sensing wire.

If you bought a new Jayco, it will probably have an AES fridge.

Here is a link showing many options on how to correctly wire up an AES fridge:

https://www.caravansplus.com.au/pdf/AES-installation.pdf

There is one that shows the option if you have a VSR.

I have no idea how Jayco wire the D+ lead back to the 12-pin plug. There doesn't seem to be a set standard.

There are usually two sources of 12V provided at the 12 pin plug.
One, on pin 2 (which is usually wired on most cars as the reversing lights) which goes to the AUX input of the BmPro J35. This will suppy 12V to charge your van battery whilst you are driving. This is usually a permanent conection to the 12V from your car battery, but depends on the particular vehicle.
The other is wired to the heavy duty pins to run the fridge.

If you are in lockdown, also download and read the BmPro J35 Manual. When you have problems with 12V make sure you post that you have a J35 otherwise, again, you will get answers to your questions by people who have the earlier Setec ST series power supplies and the answers, although well meaning and coming from people with a wealth of practical experience may not be related to your particular equipment.

take care
Mike
 

Drover

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#9
Fridge Switch is a movement sensor fitted to the 12v supply from tug to fridge, usually fitted at the terminal at back of fridge, that way doesnt matter what way you are routing the supply it cuts power when stopped and works with either type of fridge operating system, once you start driving it starts working again, battery never gets drained. The AES system will just wait till it gets power then start working .
 

jazzeddie1234

Active Member
May 19, 2016
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Mandurah
#10
I have an auto select 3 way fridge and jayco simply connected the sense (D+) wire to the 12v feed coming from the van 12 pin. So the fridge switched over when alternator 12V was detected. This works if you have a relay connecting the alternator to the tug 12 pin which is operated by the ignition switch (or VSR).

Just to be different I run a direct feed from the alternator (no relay) to the tug 12 pin and a second cable from my ignition to the D+ via an unused pin.

A useful safety feature on my fridge is that it waits 15min before switching from 12v to gas which I think is to prevent any sparks when you pull in to refuel
 

Gero

New Member
Jun 10, 2020
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Geraldton
#11
I have picked up new expanda outback and after reading this thread and with the link supplied by mikerezny thought i would install fridge switch on AES fridge following instructions on number 3 of the five options.

It shows a single positive wire going from the fridge switch to the D+ terminal. Does this wire come from the vehicle positive or the fridge positive on the fridge switch?

I thought it would be easy to work out but I am getting dumber as I get older. Cheers.
 

mikerezny

Well-Known Member
Sep 11, 2016
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#12
I have picked up new expanda outback and after reading this thread and with the link supplied by mikerezny thought i would install fridge switch on AES fridge following instructions on number 3 of the five options.

It shows a single positive wire going from the fridge switch to the D+ terminal. Does this wire come from the vehicle positive or the fridge positive on the fridge switch?

I thought it would be easy to work out but I am getting dumber as I get older. Cheers.
Hi,
In this diagram, the fridge heating element is not actually switched by the fridge switch. The fridge switch is wired to just switch power to the D+ wire. Then the fridge will manage switching on the heater element.

It took me a while to work it out. It is quite a subtle way of doing it. The fridge switch just provides power to the D+ wire when the car is moving. And then the fridge switches over to 12V to power the 12V heater element.
So, the fridge switch is not connected to your vehicle 12V at all.

The12V input to the fridge switch comes from the van battery, same as how the fridge electronics is powered. The 12V output from the fridge switch goes to the D+ input terminal of the fridge. The heavy duty 12V wiring from your vehicle battery / alternator goes directly to the 12V input to the heating element.

So in order of operation.
1: you need 12V from your van battery to power the fridge electronics, whether the fridge is on gas, 240V, or 12V. These are the control terminals.
2: you need 12V direct from your vehicle to power the 12V heating element. Heavy duty since it needs to handle 15A with negligible voltage drop. These are the DC element terminals.
3: you need to tell the fridge when 12V is available so it will switch to running off 12V. This is done by connecting input to the fridge switch from control terminals. Then connecting the +ve output of the fridge switch to the D+ sensing terminal.

Hopefully that makes sense.

take care
Mike
 
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Drover

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#13
It shows a single positive wire going from the fridge switch to the D+ terminal. Does this wire come from the vehicle positive or the fridge positive on the fridge switch?

It doesn't matter where the D+ wire sources its power, (though it will be sourced from the tug) once you stop if you have the Fridge Switch wired in the D+ circuit, once you stop the Fridge switch will disconnect and the fridge AES will shut down the 12v heating element and start searching for 240 or Gas, thats why its important to always shut the gas down when hitching up.................. it will also throw a fault light but this can be reset later with the On/Off button.