Thread: Power from White Plug to Anderson Plug

Originally Posted by gghaggis

A dedicated line is always a better solution, however it's more complicated and I don't think it's necessary for loads under 20A or so. I've used the switched (ignition -fed pin) option in the S plug over the last 6 years to power the fridge in the various caravans/campers I've had (up to a 175 ltr fridge), and in all that time I've never had an issue. Yes there is a voltage drop (around 1 to 1.5V at full load), but the system works well enough and is switched, so you don't have to worry about forgetting to disconnect it.

Cheers,

Gordon

Hi Gordon,

Where can I buy an adapter or did you make it up yourself?

This issue is appearing in a few threads now which is great becasuse like others, I have not been keen to start adjusting wiring on my new LR4.

I have learned quite a bit from my research and would offer this here if I may.

The 12S socket supplies two power options (at least on the D4) the manual for your car will tell you the rating of the fuse for your earlier disco. For mine it has a 15A Ignition positive and a 30A permanent supply. Many connect fridges to the 15A ignition positive in preference to the permanent supply to protect their battery from draining when stopped. This is fine if your fridge draws less current than the circuit can supply but if your fridge is rated higher than 15A and you wish to use the 12S socket then this should be achieved via the 30A permanent supply using a voltage sensing solenoid which is sensing assessing the voltage of the 30A supply to see if the alternator is running and isolating the fridge when not.

If you want to utilise the wiring in your disco then you have a couple of options.

1) Dont run fridges in your trailer from the ign Positive if it draws over 15A
2) Use the 30A Permanent live 12V with a VSR which switches your fridge off when stopped.
3) Fit a dual battery system to your car and run the trailer accessories from the auxhiliary battery.
4) Fit an auxhiliary battery in your trailer (if you don't have one already) run the fridge from this battery and fit a 12V/12V charger to charge the battery while towing.

My preferred option is 4 as some in this thread will already know for the following advantages:

No need to change the disco wiring or sockets (so long as your charger doesn't draw more then 30A

No need to be concerend at losing volts on the long run to your trailer as the chargers will step this up in the trailer itself (always mount the charger close to the trailer battery).

No worries about flattening the car battery ever, as the charger senses when the alternator is running and only charges then. (no need for the solenoid).

A decent charger will also accept a solar input. Mine has an MPPT controller ensuring a max 30% increase in the charging efficiency. This means that you do not need a regulator on your panels and the panels can be left connected while running ( if mounted to the roof of your trailer) The charger circuit utilising a relay to switch between car 12V and solar 12V or they may be connected (as I am doing) so that when parked I pull the 12S plug out of my vehicle and connect it to the lead running from my portable solar panels.

The socket, used in this way, is being so more akin to what it was designed to do. Feed an onboard charging system while the on board batteries feed the onboard appliances. Remember, us Poms dont go offroad in caravans in the UK! Well not many do as most will tow on tarmac to a site, pitch and plug in! And theres not much current draw on a fridge which is just as cold as ambient JOking here but in UK you don't need massive fridges as they sinply don't have to work as hard as Aussie ones.

Some of the damage occurring to the 12S sockets can be avoided. Earlier in this thread someone reported that their centre earth had a wire going to the ignition earth in the 12S socket. This is a remedy to provide two returns for the earth current 'to share the load' as it is often the case that the centre pin (also used for guiding the socket and plug together) can become compressed and have a poor contact. I understand these to be brittle though, so take care if trying to splay them again. The practise involves looping a piece of wire between this centre earth and the ignition earth pins in both the plug and socket which should effectively halve the current travelling back to negative in each of these circuits keeping things cooler. (allowing for circuit resistance differences as mentioned below)

Take a look at a tip on this very subject here
Totalcaravancare.co.uk » Tips and advice from Total Caravan Care

Outasight mentions drawing current from two 15A circuits to get 30A but if you have two 15A circuits I don't advise that you do this. There is always some imbalance due to circuit resistances (Connections, cable sizes etc) and one WILL draw more than the other. More than 15A will blew your fuse and then very quickly the other one moreover you will be momentarily overloading your cabling on the higher resistance circuit. Sorry Outasight but I needed to offer this point in order to prevent dissapointment or worse

If you simply want to power massive electrical loads then use an isolator and run a large diameter (6B&S) cable through your disco to the rear and plug into it. But if you want to utilise the 12s socket then consider the above advice.