Electrical Burnt another 12 pin plug

Macca_75

Well-Known Member
Aug 3, 2016
500
450
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SE Suburbs, Vic.
#1
So the fridge stopped working on 12v connected to car again this weekend. Checked the plug and sure enough I have melted to middle of the top row of pins (which is what the fridge connects to).

2nd time round so 1) I have been careful to ensure the pins are fine when connecting the plug and 2) This won't happen again.

What have others done? How is your fridge wired to run when connected to the car and travelling.
 

millers

Active Member
Mar 25, 2011
211
156
43
Adelaide
#2
I would suggest that changing to Anderson is required for more current carrying capability and better connection.

Heat generated at the connector means that the cable to connector (both sides) and / or connector to connector resistance is too high generating heat that can not disipate quick enough.

Most mechanical connections (screw type) have issues with contact surface area and the connector to connector oxidises over time increasing the resistance and therefore the heat.

Caravaning been on the back burn for a while, but I have been looking at the 7 pin flat combined with 50 Amp Anderson and make the caravan cable so that I plug in as a single action.
 

Drover

Well-Known Member
Nov 7, 2013
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Cooloola Coast, QLD
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#4
You will probably find the weight and movement of the cable is pulling the socket terminals, as for drawing power for the fridge from your Anderson it shouldn't be a problem really just use the wiring from your 12 pin, van side, and tap it into the Anderson, if your Anderson pins are soldered then dismantle them , join up your fridge wires and resolder the pins, if crimped you could just piggy back solder them but I would just cut and replace the pins with new ones soldered in....the Anderson is rated more than enough to handle the current and the tug side for fridge and 12v should be on the same circuit...Does seem strange to have battery charge on an Anderson and fridge on 12 pin, go over and check the circuits, before you mod them...
 

Macca_75

Well-Known Member
Aug 3, 2016
500
450
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SE Suburbs, Vic.
#5
The Anderson definitely recharges the battery. My only *concern* is if I wire the fridge to the Anderson, 12v will always be available to the fridge (regardless if the car is connected or not). So if the fridge were ever changed from Auto to DC, I would flatten by battery very quickly.....

May need to see if I can fit a relay off something to detect the car and run the fridge via this
 
Mar 13, 2017
770
705
93
Ferny Grove, Queensland
#6
The Anderson definitely recharges the battery. My only *concern* is if I wire the fridge to the Anderson, 12v will always be available to the fridge (regardless if the car is connected or not). So if the fridge were ever changed from Auto to DC, I would flatten by battery very quickly.....

May need to see if I can fit a relay off something to detect the car and run the fridge via this
Hi @Macca_75 , I got rid of my old 7 pin plug and refitted a 12 pin plug. The top 5 pins in the 12 pin plug are rated at 35A and the bottom 7 are only rated at 15A. I have a dedicated pair of 8 B&S cables running to van fridge and connected to tug with Anderson plug. I also have a dedicated 8 B&S single cable running to Setec to charge van battery. I use one of the heavy duty 35A pins in the 12 pin connector for that and another of the 35A pins as a heavy earth return between van and tug. The bottom 7 pins (15A) are only used for tail/stop lights, running lights, turn indicators, van electric brakes and a lighter separate earth return to tug for these loads. Both the fridge wires and the wire for charging the van battery from tug operate through a Voltage sensitive relay and a 100A circuit breaker. The VSR will prevent any discharge power to fridge once tug battery voltage drops below 12.6 volts. It also isolates the van battery even though the charge line to van battery incorporates a power diode in series (in Setec) which prevents current bleeding back to tug battery. When connected to tug and engine running, relay connects the fridge/ van battery to tug alternator/battery power when voltage gets to 13.4 or above. No chance of getting a flat tug battery and no switches to remember to turn on/off. All automatically done!! Also no load on tug battery on starting as no connection made until voltage gets to 13.4 volts. Hope this gives you some ideas on how to upgrade.
 

Drover

Well-Known Member
Nov 7, 2013
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Cooloola Coast, QLD
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#9
@Macca_75 what stops your fridge flattening your battery now ????????? swap it over to the charging/anderson circuit on your tug then...............

I ran my 12pin for donkeys on the Jeeps no drama but on The Ute the plug was mounted the other way with the HD pins on top, the cable pulled down a fraction and the HD pins moved a mm or so and burnt out, changed to 7 pin and ran the fridge power circuit via an Anderson, no 12v charging circuit on my rig as the solar does it all, my van cam draws its power from the frdige circuit then if cam drops off I know the fridge has stopped, has happened sometimes, just dirty contacts.
7 pin is way cheaper than a 12 pin anyway and with an anderson you can better sized cable.
 

Macca_75

Well-Known Member
Aug 3, 2016
500
450
63
44
SE Suburbs, Vic.
#10
@Macca_75 what stops your fridge flattening your battery now ????????? swap it over to the charging/anderson circuit on your tug then...............

I ran my 12pin for donkeys on the Jeeps no drama but on The Ute the plug was mounted the other way with the HD pins on top, the cable pulled down a fraction and the HD pins moved a mm or so and burnt out, changed to 7 pin and ran the fridge power circuit via an Anderson, no 12v charging circuit on my rig as the solar does it all, my van cam draws its power from the frdige circuit then if cam drops off I know the fridge has stopped, has happened sometimes, just dirty contacts.
7 pin is way cheaper than a 12 pin anyway and with an anderson you can better sized cable.
At the moment my fridge runs directly from the car, not the van battery. This is the 2nd plug on the van I will have to replace. Might have to get an Autoelec to give the car a once over.
 

Drover

Well-Known Member
Nov 7, 2013
7,900
13,988
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Cooloola Coast, QLD
www.expandasdownunder.com
#11
No, I didn't mean van battery @Macca_75 I meant the car battery, if it your fridge doesn't flatten your car battery while it was wired in the 12 pin then that means you have something fitted somewhere ??? either in car or van that acts as a fridge switch, therefore remove the wires from the 12 pin on car side and fit an Anderson plug, Do the same on the 12 pin on van and bingo no dramas it will all work as before just no meltdown......if your 12pin will still connect up it will be okay for all the other wires as they don't draw as much.....

Otherwise just replace.........If the HD pins are on the upper level of your socket it will happen again just change to Anderson and save future hassle.........I've been there....,.......you don't want to run your fridge off the van battery, ever.
 
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