12 PIN Wiring - Brake Controller - 12 Volt Fridge Hotwire - 12 Volt Hotwire DIY

[expanda]

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Disclaimer: If you have no experience in this type of job it may be best to seek professional assistance. Any auto electrician should be able to do this work for you and as a caution you need to know what your doing when performing this work. I accept no liability from damage caused by performing this install yourself. It is easy enough but its electronics and safety and there is always an element of risk involved so proceed with caution!

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Ok so boring stuff over I am going to be installing the following for the expanda over the next few weeks so will document the fun!

Alot of this is overlooked if you are on your first van. In most cases you can get this factored into your overall purchase of a new van but sometimes its not always the case.

Now onto the technical details of what we are doing; all of the below mentioned items will be installed by a 12 PIN plug on the tow vehical as the Jayco Expanda when optioned with a 150LT fridge is pre wired with a 12 PIN plug. This is to accomodate everything listed a little further below.

There is much debate some technical and some muscle talk over wether to use an anderson plug vs the 12 PIN plug and that debate can be had out in another topic!

This guide is for the 12 PIN plug and 12 PIN plug only as it comes standard with any Jayco Expanda that has a larger fridge than standard and I want to keep it as simple as possible. If you believe strongly in another setup (anderson) or similar please feel free to write it up!

So what am I installing....

1) A hotwire to power the fridge whilst driving - The hotwire is a wire that will go from the battery directly to the 12 PIN trailer plug on the back of your car to power the fridge in the Jayco Expanda as you are driving. This will be configured with a relay that turns the power of to the wire when your car ignition is turned of. The relay is essential as if you did not cut the power to your hotwire after turning the key of you would flatten your car battery quite quickly.

2) An earth wire for the fridge circuit - This is a dedicated earth wire for the fridge and runs from the battery to the 12 PIN trailer plug.

3) A hotwire to power the battery charger and or activate your 12 volt lights et whilst the car is connected to the trailer plug - Again this will utilize a relay so power is cut of to the hotwire when the ignition is disconnected.

4) An electronic brake controller which will control your brakes whilst driving -

So let's get started with the wiring schematic I drew up for everything bar the brake controller (that comes later )....



Now click on the picture and you will see the intended diagram. Don't worry if it is confusing I will be posting some pictures and explaining in more detail as we go along.

So firstly to explain what the connections on the 12 pin plug will look like first familiarise yourself with the official 12 PIN plug pin diagram on the Narva website and the one on campertrailers.org.

http://www.campertrailers.org/trailer_wiring_diagram.htm

http://www.narva.com.au/products/browse/wiring-diagrams

So based on our schematic and what Jayco wires as standard the pins we will be using on the 12 PIN plug are as follows -

Hotwires x 2 -

a) 12 PIN Plug PIN 9 = Hotwire for the fridge
c) 12 PIN Plug PIN 2 = Hotwire for your electrics / battery charger

Earth x 2 -

b) 12 PIN Plug PIN 10 = Fridge earth
b) 12 PIN Plug PIN 3 = Normal trailer pin earth

Here is a diagram putting the two sites together for the 12 PIN plug.



Important note: PIN 2 shows as "Reverse" on the 12 PIN diagram on the Narva site, don't worry most caravans do not have reverse lights so Jayco uses PIN 2 as the hotwire pin confusing I know but Jayco has done it for a reason and we must match our wiring to theres.

Also a further note and a bit of troubleshooting if you are getting blow / fuses relays and have not installed your hotwires yet it always pays to check if you have this reverse wire circuit hooked up to PIN 2 as this could be cause of your grief.

 

[brookes2622]

Hi. I have a 17.56-2OB coming with the 150l fridge so it has the 12 pin connector. My car has an 7pin plug, AUX battery with Anderson plug. I am thinking it would be best to splice into my current 6B+S wire for the Anderson to supply pin 9 and 2. Then run new earth for 10 and 3. Does that sound OK?

 

[macca]

Expanda, can I ask why you have not decided to use an Anderson Plug for the Fridge line. The research I have done shows the Anderson to take twice the amps of a 12 pin. 12 pin looks neater and simpler and I know its an opinion thing but I thought the 12 pin restricted the amps like an egg timer. But I am a novice so I am keen the hear the benefits of 12 pin.

Geoff

 

[boots33]

Hi brookes
If your car is already fitted with an anderson plug you would probably have been better off getting jayco to wire the van with an anderson plug as well. if it is too late to make the change then yes what you list above will work for most situations. Be aware that you will also need to add inline fuses to both those circuits, the fridge supply will require a 20a fuse and depending on the setec unit fitted you will need a 20a fuse for a setec-20 or a 30a fuse for a setec-35

 

[boots33]

Expanda, can I ask why you have not decided to use an Anderson Plug for the Fridge line. The research I have done shows the Anderson to take twice the amps of a 12 pin. 12 pin looks neater and simpler and I know its an opinion thing but I thought the 12 pin restricted the amps like an egg timer. But I am a novice so I am keen the hear the benefits of 12 pin.

Geoff

Hi Geoff
Narva rate their 12pin plug as 15a for the seven small pins and 35A for the 5 larger pins so yes the anderson plug can carry more current than a 12 pin plug. The real question you need to ask is how much power are you likely to need supplied from your tug, for most people the requirements for the van while travelling are fairly low. a 150ltr fridge will draw 15a and if your battery is not overly flat you will only draw a few amps to supply it's needs and usually that's all you need. Of course if you have given your van battery a real workout and flattened it severely you will be giving that little pin2 a real test of its abilities! The debate on which type of plug setup to use will rage on forever, in practice both systems will work fine and largely comes down to personal choice. The anderson is certainly the most robust of the two and would be my choice if i were planning a trip around oz but for the weekend warriors like myself the 12pin is usually fine.

 

[brookes2622]

The issue I have is that the van is not new so already comes with a 12-pin plug. I have to go and pick it up so have a 5 hour drive to complete but need to be able to . I could make up an adapter to go from the 12-pin plug to the 7-pin and Anderson I already have and re-wire the van latter I suppose.

 

[Michael Watterson]

Just been looking around my van Wiring, the anderson plug which I am assuming was installed by Jayco as the wiring is all the same is directly connected to the Primary Battery.

I am assuming the Pin 9 on the 12 Pin is connected directly to the CTEK Unit?

And when the Van is on DC it is drawing from the battery?

And when travelling drawing from the battery which is being topped by by the car?

 

[boots33]

You would need to trace the wires back to make sure where they are going. On a 12pin Jayco normally uses pin 2 connected through the setec to charge the battery and pin 9 to power your fridge. As you have and Anderson as well the wiring may be different. There is really no set standard best to trace them back to make sure.

 

[jazzeddie1234]

I have wired my 12 pin slightly differently because the relay switching method was too messy for me (I have a second battery in the tray of the ute and needed a permanent 12v supply to one Anderson at the back.
I disconnected my fridge sense (D+) wire from the 12v supply cable behind the fridge and connected it to a new wire run from an unused pin on the row of 5. This pin is connected through to an ignition sense relay so now my fridge is permanently connected to 12v and switched via the ignition (this also saved me some voltage drop I would have got across a fridge supply relay).
I also linked pin 2 to another unused pin in the 5 row on the caravan side plug and moved the car side wire from pin 2 to this heavier duty one. This way I get to use a 35 amp pin for general supply but the van will still work in another vehicle (except for the fridge...)

 

[Andrew White]

I have an older Viscount with it's own battery & 12volt 20 amp DC-DC charger. I run an anderson plug from car via a dual battery kit to power the charger for van battery. Currently I have the fridge running off the van battery while driving but have found on longer trips it still drains the battery. What are your thoughts about running the fridge only off a "hotwire" via a 12 pin plug and leaving the anderson plug to run the dc charger? My Fridge is a Dometic RM2350 & the dual battery kit has been wired correctly with all appropriate circuit breakers etc. I only use 12 volt on the fridge while driving, the rest of the time I use Gas or 240 volt if on site.

 

[jazzeddie1234]

Seems like your 20A charger is not up to the job or your wiring to it is too small. You could run a separate hot (and decent earth!) cable so the fridge runs direct from the car. In either case I would measure the voltage at the fridge when on 12v to check it is at least 12 with the engine running or charger on. Also assuming the Fridge draws 10 amps, are there any other things on that could be over loading the charger? Another option is to simply bypass the charger and direct connect van battery to car (if you don't have a fancy alternator) to see if that improves things. Again you should measure the voltage at the fridge to get over 12v with the car running.

 

[Drover]

I wouldn't try to run the fridge via the 12 pin while they can be okay for some they are prone to melt downs, as for your current set up all is probably okay if the battery is showing around 12.5 say, when you disconnect the fridge it should recover back around 13 or so very quickly, it wouldn't be showing mid 13's while the fridge is hanging off it as they can draw a hell of a lot of juice..............I don't even run mine on 12 v when travelling, found no great change when I had forgotten to turn it on and now that the 12 v doesn't work I don't bother. ( must fix it though.)
If you have a multi meter check voltage at tug then check again at the DC/DC charger see if any change, assume the fridge is a direct connection to van battery. Run fridge for awhile and see if the wires to it get warm, if they do up the size of the cable.

 

[millers]

@macca The egg timer analogy is more technical than just restricting the current. The voltage drop over the total length of the run including all of the connections and devices is a function of the resistance and the current. The current does not slow down for areas with bigger resistance.
So when you run heavy duty cable to a small connector the resistance of the connector will contribute more than the cable. However the connector is short and the cable length long, the resistance contribution of the connector becomes less and less as the cable gets longer. The big issue is that the as the current draw is based on total resistance (including the fridge) and the amount of current goes through all items equally (except for the comment above where multiple connectors where used). The heat (power) generated at any one point is the current Squared x resistance. The resistance is usually very low so the heat is not an issue, however the square of the current means that as the current increases the heat increases exponentially (double the current means 4 times the heat).
Heavy duty wire has low resistance spread over the whole run so the heat dissipation is also spread over the whole length of the cable.
For the connector the heat is concentrated at the connector and has the opportunity to build up and melt the plastic and then short to other pins.
But that is usually not the problem, the problem usually comes from the ability to get the wire into the connector. In general you run an over sized cable to the connector and the Anderson has the capability to accept the oversized cable and provide a low resistance to connector. The 12 pin large plugs do not have the capacity to take as large a connector so the wire is butchered in some way to make the connection. If this is not done correctly and the wires (strands) brake then there is a high resistance over a small area. This does not reduce the total current by very much but does increase the heat produced at the connection point to the point where it melts the connector.
Added to this is the mating resistance of the connectors. Oxidisation (similar to rust on steel) and lack of firm contact between plug and socket will also cause higher resistance points where heat will need to be dissipated. If the resistance builds up to a point where the heat generated can not be dissipated then the connector will over heat and melt.

For those who know all of this apologies for the rant, hope it helps.
By the way in some industries the heavy gauge wire is attached to a small piece of small gauge wire so that the connection to the connector is correct as this will give an overall better connection. If you do this understand what you are doing and also check the resistance of the connections as well to make sure that it is suitable.

 

[jazzeddie1234]

Agree but I would still like to know why the 20 amp charger cannot maintain the battery as well as run the fridge. There has to be: another appliance drawing, a problem with the charger, or the cabling to the charger from the car is too small (most likely if installed by the average auto electrician). Remember that the dc to dc charger can only boost voltage if it is getting enough current

 

[ROnEM]

9 times out of 10, it is poor wiring, earth point or connector.

My autoelec always runs the earths for trailer plugs, anderson plugs and brake controllers directly back to the battery/ies - does not leave it to chance just earthing to the chassis. Most of his fault finding and rework business is due to bad earths or small cables.

You should be running 6mm as a minimum, but 6B&S is better. Go through the anderson plug directly to the DC-DC charger in the van, then to the battery.

Make sure you have really good earth points from the van to the car - do not rely on the chassis, or the trailer plug earth.

If this is your cabling setup, then recommend you look at your DC-DC charger as the culprit.

Cheers,

Rohan

 

[disappointed]

I've been researching Anderson vs 12 pin for a couple of days now and I have to say, I'm disappointed in Jayco. To the point I would not be surprised to hear if they were found liable for damaging vehicles, wiring their trailers the way they do.

Here's some neat little facts for you all:

An Anderson plug can carry 50amp
A 12 pin can carry 15 amps on each of the smaller 7 pins and 35 amps on the 5 larger pins.

Thus it can be said the capacity of the 12 pin connector actually exceeds the capacity of the Anderson by quite a large amount and is the better choice.

The reason for my disbelief and disappointment in Jayco is they wire the battery charger lead to one of the small 7 pin connectors when there are 5x 35 amp connectors available!

To achieve full charge in a house battery, a DC-DC charger can draw 40amps! Why put that through a 7 pin?!?!

Jayco I STRONGLY recommend leaving the 7 pin standard (partly so I can still use the reverse lights on my trailer without having them on the whole time while I'm driving around) and spread the load across the large five pins Anderson style with 3x positive pins and two negatives. Or even better, just follow the damn standard outlined by Narva.

It's ridiculous honestly, this stuff is not hard to comprehend it's real basic maths.

Regards,
Disappointed

P.S. for those of you worried about voltage drop, don't be. just install a dc-dc charger right next to your house batteries and it will maintain optimal levels for you no problem.

 

[Drover]

Doesn't surprise us at all but it's no use having a 50 amp Anderson if your wiring is not up to par and that includes the tug.......................solar panel on roof takes care of it all anyway......

 

[jazzeddie1234]

That is why I linked the original feed on the 7 pin to an unused pin on the 5. Did the same on the tug and van so it remains compatible with other vans if they just use the 7 pin