Power to the rear D4

[Redback]

I know someone metioned this, but for the life of me I cannot find the thread it was in.

The big white plug supplies power to the back but only when the ignition is on, someone mentioned it turns off or stops charging at a certain speed (80kph) Is this true:confused::confused:

I have the 2.7l.

Baz.

[gghaggis]

Are you referring to the white tow-plug on the back of the car?

If so, Pin 6 provides ignition-switched 12V power, with corresponding earth on Pin 7. There is also a permanent 12V on Pin 4 - and note there is a separate earth for this on Pin 3.

AFAIK, neither are speed dependent.

Cheers,

Gordon

[Roger]

.............. There is also a permanent 12V on Pin 4 - and note there is a separate earth for this on Pin 3.

Hi gghaggis, interested to hear about the permanent power on pin 4 of the white plug. Has anyone found its source and tapped into it for permanent internal rear power? I realise its not ideal as its off the cranking battery, but if used wisely it could be a neat easy way to get power 24/7 to a rear intenal power outlet.

[Redback]

Are you referring to the white tow-plug on the back of the car?

If so, Pin 6 provides ignition-switched 12V power, with corresponding earth on Pin 7. There is also a permanent 12V on Pin 4 - and note there is a separate earth for this on Pin 3.

AFAIK, neither are speed dependent.

Cheers,

Gordon

Thanks Gordon, and yes the white plug.

Baz.

[gghaggis]

Hi gghaggis, interested to hear about the permanent power on pin 4 of the white plug. Has anyone found its source and tapped into it for permanent internal rear power? I realise its not ideal as its off the cranking battery, but if used wisely it could be a neat easy way to get power 24/7 to a rear intenal power outlet.

Hi Roger,

It's a 20amp fused supply from the cranking battery. I think the wiring runs behind the rear passenger quarter panel, but access is different for different models (D3, D4 or RRS).

Cheers,

Gordon

[discotwinturbo]

Hi Roger,

It's a 20amp fused supply from the cranking battery. I think the wiring runs behind the rear passenger quarter panel, but access is different for different models (D3, D4 or RRS).

Cheers,

Gordon

I found the two wires in the back left panel. They both go into a white click on cable joiner (the two cables are by themselves). Just use a test light to determine which is ignition and which is permanent....or look at the back of the white trailer fitting. The ignition on was the lower cable of my D4.

So cool having much of the pre wiring done for you.

[Stuart02]

Is 20 amps enough?

[drivesafe]

Is 20 amps enough?

Hi Stuart, and it depends on what you want to use it for.

If you want to power some camp lights or run a compressor type fridge, not a problem. You could even run a small inverter but no bigger than about a 150w.

The 20 amps is not the limitation, it’s the thickness, or more correctly, the thinness of the cable that is the problem is the cable is too thin for anything that requires both decent voltage and current as this size cable will cause a fair bit of voltage drop with even a moderate current load.

It’s no where big enough to run a decent size 3 way fridge off and don’t think about charging even a small battery, you will spend more time replacing fuses then actually getting a battery charged.

[Stuart02]

The dreaded voltage drop...

[Redback]

Well we managed to get a genuine LR White plug, Purnells had one in stock, thanks Robert, wired up pin 6 and 1 (not 7) this will charge our battery in the camper and run our 3 way fridge while travelling, this plug only works when the motor is running, it won't even work if you have the ignition on, the motor has to be running, which is perfect for our setup, so all good.

We really want to thank the guys at Purnells, they have been great to us, especially with all the questions we have been asking them and sorting a few issues we have had with some small things, thanks Guys:BigThumb:

Baz.

[disco4me]

Hi Redback.

I've set up exactly the same with a Coromal camper. I was visiting the UK recently and popped into the local Land Rover dealer to have squiz at the new Evoque... I discussed the European towing set up and the nice mechanic gave me a white plug (more grey actually) to bring home. I've tried it on a short 2hr run and everything seemed to be OK with running the 3-way via the battery (it's a Coromal thing). I'll be venturing a little further over the Christmas break so I'll get a good feel for how well it works.

Happy camping....

Cheers,
John

[drivesafe]

OK folks and first a warning.

NEVER, NEVER USE A TEST LIGHT INSIDE any new vehicle.

If you have the ignition on and touch the wrong wire, you can trigger the safety air bags.

This has happened heaps of time here in Australia and there have been a number of deaths caused by this practice in the USA.

If you want to check out your trailer plug at the rear of the vehicle, fine, but under no circumstances should you ever use one anywhere else in or around a modern vehicle.

Next, the cables ( WIRES ) in the 12S ( WHITE ) plug are next to useless. They are way to thin and will cause heaps of voltage drop.

The RR has 3mm2 “WIRES” and from memory, the D4 might have 4mm2 or 6mm2 but both are still to thin.

If you have a low 100Ah battery, it can pull as much as 35+ amps, add another battery and !

The wiring is so thin that it is only barely able to top off a near fully charged battery.

Minimum battery cable size over that distance is 6B&S ( 13.5mm2 ) or 16mm2.

The fridge wiring is suitable for a compressor type fridge or the very smallest 3 way fridge.

Last but not least, the wires are ignition switched on a D3 or 2.7lt D4 and Motor ON switched on a 3lt D4

[discotwinturbo]

OK folks and first a warning.

NEVER, NEVER USE A TEST LIGHT INSIDE any new vehicle.

If you have the ignition on and touch the wrong wire, you can trigger the safety air bags.

This has happened heaps of time here in Australia and there have been a number of deaths caused by this practice in the USA.

If you want to check out your trailer plug at the rear of the vehicle, fine, but under no circumstances should you ever use one anywhere else in or around a modern vehicle.

Next, the cables ( WIRES ) in the 12S ( WHITE ) plug are next to useless. They are way to thin and will cause heaps of voltage drop.

The RR has 3mm2 “WIRES” and from memory, the D4 might have 4mm2 or 6mm2 but both are still to thin.

If you have a low 100Ah battery, it can pull as much as 35+ amps, add another battery and !

The wiring is so thin that it is only barely able to top off a near fully charged battery.

Minimum battery cable size over that distance is 6B&S ( 13.5mm2 ) or 16mm2.

The fridge wiring is suitable for a compressor type fridge or the very smallest 3 way fridge.

Last but not least, the wires are ignition switched on a D3 or 2.7lt D4 and Motor ON switched on a 3lt D4

I actually quoted the use of a test light....but I don't have one. I used a multimeter which is what my auto sparky told me to use. Could this also cause things like this to happen ? I saw him using it when he was putting my redarc brake controller in.

[drivesafe]

Hi discotwinturbo, and I’ll bet you had never heard of the danger posed by using a test light.

This has been know for at least 20 years and it’s not a case of “you should know better” it’s a case of the authorities not acting to outlaw these devices.

These devices have passed their use-by date and the fact that the average person, like yourself, has no idea of the danger they pose, makes it imperative that test lights should no longer be used or even be available.

To your question, digital multi meters are completely safe to use and will NOT trigger safety air bags.

[Redback]

Hi discotwinturbo, and I’ll bet you had never heard of the danger posed by using a test light.

This has been know for at least 20 years and it’s not a case of “you should know better” it’s a case of the authorities not acting to outlaw these devices.

These devices have passed their use-by date and the fact that the average person, like yourself, has no idea of the danger they pose, makes it imperative that test lights should no longer be used or even be available.

To your question, digital multi meters are completely safe to use and will NOT trigger safety air bags.

Just so you know Tim, I have never used a test light, we use a Multimeter that was given to us by a good bloke;) AND the white plug is only used to power the Arrid twin charger that we have had in the camper since we got it, the fridge runs off the battery, we have been doing this for as long as we have had the camper, back before we had our first Disco, this only happens while travelling, when camped the fridge goes to gas and the battery is charged by a solar panel.

This will change a little further down the track when the 3way goes(it's rusting away)

Baz.

[wcody01]

Hi guys,

new to this forum stuff so please bear with me

ive read about getting power to the back to charge batteries and run fridges.
I would like to have a anderson plug at the back not to charge batteries but to run my 3 way fridge HOWEVER, the 3 way fridge draws 23 AMP on 12 volt

any ideas how to safely get this sort of power output to the back without upsetting the whole system?

Cheers

[Redback]

Hi guys,

new to this forum stuff so please bear with me

ive read about getting power to the back to charge batteries and run fridges.
I would like to have a anderson plug at the back not to charge batteries but to run my 3 way fridge HOWEVER, the 3 way fridge draws 23 AMP on 12 volt

any ideas how to safely get this sort of power output to the back without upsetting the whole system?

Cheers

Only way to run a 3-way on 12v is to have the car running all the time.

Baz.

[Graeme]

Pin 4 in the white trailer socket has a 30A fuse in the circuit that is always powered and pin 6 is ignition/engine running power. A relay could be inserted in the permanent power line and operated by the ignition power so that the fridge operates only with the ignition on. However I suspect the 30A wire is not heavy enough to avoid significant voltage drop when drawing 23A at the back of the vehicle, regardless of whether or not sufficiently heavy gauge wire is used from there to the fridge.

[wcody01]

Pin 4 in the white trailer socket has a 30A fuse in the circuit that is always powered and pin 6 is ignition/engine running power. A relay could be inserted in the permanent power line and operated by the ignition power so that the fridge operates only with the ignition on. However I suspect the 30A wire is not heavy enough to avoid significant voltage drop when drawing 23A at the back of the vehicle, regardless of whether or not sufficiently heavy gauge wire is used from there to the fridge.

we only ned the power when driving down the road. at other times it wil run on gas

any power will be better than what we have now ie nothing. will the voltage drop affect the vehicle in any way? or just the eficiency of the fridge? our biggest concern is damaging or compromising the vehicle and its warranty.

[drivesafe]

Hi wcody, if you use the cables as Graeme suggested, you won’t have any warranty issues.

From what you have posted, I take it you are talking about carrying the fridge in the back of your D4.

If so, you could make up a lead by tapping into the 30 amp cable and bring it into the cargo area via the tow hitch compartment on the passenger’s side.

You could then tap into both the positive and negative wires going to the cigarette power socket located just above tow hitch compartment.

You then use these two wire from the power socket to run a relay to control the power in the lead. Just add your Anderson plug to the end of the lead.

Your fridge will turn on and off with your ignition switch.

You can leave the lead in the tow hitch compartment when not in use.

[wcody01]

sorry for the confusion.

we have a 24 foot jayco sterling which has the 3 way full size fridge freezer in it.
when stopped at a camp site it runs on either gas (free or bush camp) or 240volt (caravan park)
while travelling it should run on 12 volt power drawing 23 amps. This is provided by a dedicate anderson plug on the van not hooked in to the trailers wiring loom.
the cautious auto electrician who my local LR dealer has had the electric brakes fitted with rejected the idea of being able to power the fridge of the car whilst driving saying it woul be too much to draw continuously (once again while driving) on the system and would possibly cause the vehicle to shut down.

From what i read here it would be possible to use the already existing power/cabling at the back of the car (white plug) to connect an anderson plug (realyed/triggered to the ignition) for the fridge to plug in to??

my limited knowledge and skills would see me going to opposite lock to have it done. my analytical mind however tells me that if the circuit has a 30amp fuse it should be able to handle a draw of 23 amps.......

PS the D4 3.0L is awesome for towing a nearly 3 tonne van

[Graeme]

my limited knowledge and skills would see me going to opposite lock to have it done. my analytical mind however tells me that if the circuit has a 30amp fuse it should be able to handle a draw of 23 amps.......
LR obviously are OK with drawing up to 30A in that wire because that's the fuse rating they fitted. The voltage drop would be at the fridge, not the powered end.

[drivesafe]

Hi again wcody, and again as Greame posted but make sure you also have a decent earth return at the plug as well.

The amount of voltage drop you are going to get means you will be lucky to be pulling 20 amp, so the cable and fuse are fine.

[gghaggis]

sorry for the confusion.

we have a 24 foot jayco sterling which has the 3 way full size fridge freezer in it.
when stopped at a camp site it runs on either gas (free or bush camp) or 240volt (caravan park)
while travelling it should run on 12 volt power drawing 23 amps. This is provided by a dedicate anderson plug on the van not hooked in to the trailers wiring loom.
the cautious auto electrician who my local LR dealer has had the electric brakes fitted with rejected the idea of being able to power the fridge of the car whilst driving saying it woul be too much to draw continuously (once again while driving) on the system and would possibly cause the vehicle to shut down.

From what i read here it would be possible to use the already existing power/cabling at the back of the car (white plug) to connect an anderson plug (realyed/triggered to the ignition) for the fridge to plug in to??

my limited knowledge and skills would see me going to opposite lock to have it done. my analytical mind however tells me that if the circuit has a 30amp fuse it should be able to handle a draw of 23 amps.......

PS the D4 3.0L is awesome for towing a nearly 3 tonne van

Must be a big fridge! My 170ltr 3-way requires a 170W battery connection, which at 12V implies it would draw around 15amps maximum. I easily power that via an Anderson plug through the powered pin of the white socket on the back of the car (that way I can't accidentally drain the battery). Never had issues with lack of cooling in the fridge or overheating of wiring.

Cheers,

Gordon

[wcody01]

Hi Gordon

yes it is a big fridge, 180L AES with a seperate freezer. spec sheet says 23 AMP on 12 volt so that is what i am going off. natuarlly i dont expect it to cool on 12 volt just maintain would do

good to here you've had no problems with the wiring through the white plug. what did you use as the earth wire?

[Robocop]

I've seen the white plug, there was also one on my FL2, have no idea what it was for. Aside for constant +v what do the other pins do? I'll take a stab in the dark & guess its for powered trailer brakes? What else could it be?

[Graeme]

Only reversing lights, 2 HD earths and ignition power.

[Robocop]

Oh good, perfect for hooking up my flux capacitor then..

[Canaussie]

Just curios,

Has anyone actually done a voltage drop calc?
What kind of distance of cable are we actually dealing with?

Also has anyone looked up the specs on the cable that is being used to see what current carrying capacity they are capable of?

I'm a industrial sparky and I'm quoting from memory but I believe 4mm cable is rated at about 32 to 40 amps, closer to 32 due to being enclosed. I think 6 mm is rated to 50-60A. Just curious on the specs. It's one thing to say voltage drop this and that but a simple calc will sort it out.

IMO is all


Cheers


Oh ya this is my first post......lol:p

[Graeme]

The wiring diagram shows it as 2.5D. Other wires elsewhere on the vehicle (eg going to the suspension ecu) that are also shown as 2.5D have about a 2.5mm dia conductor, 1.5D have 1.5mm and 0.5D have 0.5mm diameter conductors.

A 20A load and a volt meter will do a better job at sorting it out as its length is unknown.

[gghaggis]

The wiring diagram shows it as 2.5D. Other wires elsewhere on the vehicle (eg going to the suspension ecu) that are also shown as 2.5D have about a 2.5mm dia conductor, 1.5D have 1.5mm and 0.5D have 0.5mm diameter conductors.

A 20A load and a volt meter will do a better job at sorting it out as its length is unknown.

I measured it with my fridge attached and wrote it down somewhere - at the fridge it was something like 12.7V with the engine running (as I use the powered pin from the car). I'll see if I can find the exact figure.

Cheers,

Gordon

[Graeme]

Was that running a 3-way or a compressor fridge?

[gghaggis]

Was that running a 3-way or a compressor fridge?

Fridge as above - 170 ltr 3-way (with separate freezer)

Cheers,

Gordon

[gghaggis]

I measured it with my fridge attached and wrote it down somewhere - at the fridge it was something like 12.7V with the engine running (as I use the powered pin from the car). I'll see if I can find the exact figure.

Cheers,

Gordon

Just went down to the car to check my trusty notebook, and I'd logged the figures there. Not as good as I recalled :(

Engine running and 13.4V at the battery, I got between 11.9 and 12.1V at the fridge. The regime was to run the caravan fridge off the car during the day travelling, so never more than 9hrs at that voltage.

Cheers,

Gordon