Wiring with AUX battery in Car

brookes2622

Active Member
Jun 24, 2012
383
38
28
Bywong NSW
#1
I've just picked up my van and just threw on a 12 pin plug to get it home, but now it's home I need some wiring advice. I have a second battery in the car run off an isolator that powers the winch etc but also powering an Anderson plug on the back. This was for my old camper, but now I have a larger fridge and a battery in the van so which would be better? Put the Anderson wiring in the 12-pin plug lose the Anderson or ditch the 12-pin and put a Anderson on the van (will the van wiring even handle the current as I have 6 B&S going to the Anderson)?

Also, about pin 2, can I just run it off the Anderson, continuous 12v off the AUX battery in the car without issue?
 

leesy

Active Member
Jul 26, 2012
471
36
28
Lysterfield
#2
Advice I was given was, Anderson from dual battery system straight to the van battery (fused) and the "hot" wire via the pin plug connection to run the fridge in transit, then switch to 240 v or gas on arrival at destination. I have only been on the forum for a few days but I have read posts from a couple of members that really know this stuff!! My advice was from my jayco dealer the asked my auto elec that did my dual batt and other mods to the big GU Patrol. Cheers
 

achjimmy

Well-Known Member
Jan 24, 2011
3,025
3,397
113
#3
Hey Brookes

Check if your winch is wired through the auxiliary battery, that is not common to be on the aux alone.

I found with both vans the small gauge Hotwire was useless to run the fridge. I was advised that if I shared the fridge wire with the battery wire it would slow charging up considerably. So I ran a heavy wire from the car aux battery to an Anderson plug to van battery. I Then ran a second a heavy wire from the start battery to the van fridge, you can either use a fridge switch or a second isolator to switch it ( my choice) depending on the gauge of wire you can either split the cable over two negs and pos on a 12 pin plug or run a second Anderson (my choice) the 150 litre fridge runs fantastic on 12 v now and even freezes the ice cream and the battery's get a great charge.
 

brookes2622

Active Member
Jun 24, 2012
383
38
28
Bywong NSW
#4
Hey Brookes

Check if your winch is wired through the auxiliary battery, that is not common to be on the aux alone.

I found with both vans the small gauge Hotwire was useless to run the fridge. I was advised that if I shared the fridge wire with the battery wire it would slow charging up considerably. So I ran a heavy wire from the car aux battery to an Anderson plug to van battery. I Then ran a second a heavy wire from the start battery to the van fridge, you can either use a fridge switch or a second isolator to switch it ( my choice) depending on the gauge of wire you can either split the cable over two negs and pos on a 12 pin plug or run a second Anderson (my choice) the 150 litre fridge runs fantastic on 12 v now and even freezes the ice cream and the battery's get a great charge.
Yeah my winch is only running off the AUX battery as it sit closer to the winch then the starter. I have an isolator connecting the AUX to the primary so all is safe.

When you say "heavy wire" what does that mean? I ran 6 b&s to my Anderson and I wonder if I will need to replace the van wiring to match. So I'm thinking that I'll ditch the 12 pin on the van and add an Anderson plug.

Now for the pin 2 wire what runs off it? Would it be sensible to run it off the house battery only and rely on the Anderson with the better wire? What runs off it?
 

achjimmy

Well-Known Member
Jan 24, 2011
3,025
3,397
113
#5
Yeah I ran two lots of twin 6 B&S but was advised that 8 B&S was adequate for the fridge, I just couldn't be arsed getting a different gauge. But if you were trying to use the 12 pin plug 8 B&S split across two pins each is about the limit of what would fit. And yes I changed the wiring in the van, running 6b&s down each chassis rail, one to the batteries and the other from the start battery to the fridge. A lot of work but so far the results have been excellent.
 

chartrock

Forum Patriarch
Staff member
Sep 26, 2010
5,792
6,723
113
80
Gold Coast Hinterland
#6
My son used to install solar panels and has had a fair amount of wire left over. It is labelled 6mm DC so I have used it to rewire my truck with two Anderson plugs and fitted an extra one to the van going directly to the fridge. The van had been wired by the dealer for portable solar with one anderson plug.

Van connector wiring.jpg

I now have to wait for a chance to test it. :mmph:
 

achjimmy

Well-Known Member
Jan 24, 2011
3,025
3,397
113
#7
My son used to install solar panels and has had a fair amount of wire left over. It is labelled 6mm DC so I have used it to rewire my truck with two Anderson plugs and fitted an extra one to the van going directly to the fridge. The van had been wired by the dealer for portable solar with one anderson

I now have to wait for a chance to test it. :mmph:
that's pretty much what I did except I used 6b&s (13mm) and instead of an ignition relay used a VSR so I didn't have to go cutting into the loom under the bonnet. It works well Chartrock.
 

brookes2622

Active Member
Jun 24, 2012
383
38
28
Bywong NSW
#8
Ahh speaking of b&s, wherever I mention 6 b&s replace with 8.....:embarassed:

Am I right in thinking that the two larger pins on the 12 pin are direct to the fridge and pin 2 is to charge the battery? Would anyone have a wiring diagram for the 17.56-2?