Using car to power 12v in caravan

[twindaddy]

Hi all
As always I'm after some of your vast experience and knowledge...
When i bought our van privately last year, the prev owner gave me an extension type lead which has towing elecs plugs on each end. each plug only has 2pins in it and he said it can be used to draw power from the cars towings electrics to power the 12v lights etc in the van if the leisure battery goes flat when not on ehu.

Which sockets/plugs should be connected and do i need engine/ignition on etc. My van has twins elecs and the tow vehicle has 13pin with adaptor on for 2 7pin .
Thanks
TD

 

[WoodlandsCamper]

The ignition does not need to be on, but you must disconnect the leisure battery. Pins 9 & 13 on a 13-pin connector provide a permanent 12V supply, used by the van to charge the leisure battery when travelling. On 2x 7-pin connectors you use the grey auxiliary connector. The black connector provides the road lights.
Try this link
http://www.caravantalk.co.uk/community/topic/68502-twin-7-pin-plug-to-13-pin-conversion/

 

[colin-yorkshire1]

hi TD, not sure you can use it if the car has a 13pin plug, because :-
1. there is no aux wire in the system,
2. even if you use a converter or a set of tails ie 2 -7s to 13 because the wires that power the black plug don,t have a power wire only the lights as it is the grey plug that carries the power wires, and of course the extension you have fits the black plug.
3. the extension you have "I had one also" was for when (on the old wiring specification) the black plug carried a aux wire "blue" to power the vans internal lights, but now I think it is used for the reversing lights.
if you are a DIY,er it may be possible to cut off the black plug and change it to a grey one "to use on the tails " incooperating the live perminant feed to power the extension forgot the exact pin no this would give the the black plug at the caravan end the same as if using the old wiring system, ie like the blue wire used to do.
it also depends on wether the van is wired in such a way that still uses the now defunct wire , this may be possible if it is an oldish van that uses a habitation relay wired into the black socket, or a habitation relay on the new wiring system "grey plug via perminant feed" seeing as how the previous owner gave you the extension and assumidly used it I would think the former could be the case.
so IMHO no you cannot use it as is but it could be modified to do what you want it to do.

 

[colin-yorkshire1]

hi TD, since my last post I have been having a think because I am sure the wiring pin configuration has changed.
on doing a bit of research it seems the pre 1998 pin configuration is different from the post 1998 in so much as the grey 12s plug
had 3 power wires pre 1998 and only 2 post 1998 the difference being pin 2 this (pre1998) was for battery charging pin4 was for internal lights pump ect, and pin 6 was for fridge. however (post 1998) pin 2 is deleted and used as a spare while pin 4 carries the power to the van for internal and battery charging (via a relay in the van) pin 6 remains for the fridge,
now I had a thought if your van is a 1996 sterling and therefore pre 1998 its wiring would include the use of pin 2 and pin 4 for power however seeing as how the tails (that you use to connect to the cars 13 pin) may well be wired circa post 1998 and not have enough power wires to use the extension that you have been given, it would still work if rewired but you would have to know exactly which wires feed which circuit,
I am writing this on the assumtion that you have already tried to plug in the extension and it did not work because the pin configuration was wrong. or the power from the cars plug only works with the engine running "ie via a smart relay".
or am I being too technical, see here for what I mean http://www.thebritishcaravannersclub.co.uk/Help%20Advice/information/wiring.php

 

[ProfJohnL]

Hello colin.
Last post 2.54 am - Working the night shift?

 

[colin-yorkshire1]

Hello colin.
Last post 2.54 am - Working the night shift?

hi John, no just old grumpy not being able to sleep again

 

[twindaddy]

Thanks

I did try it when out last year as my charger gave up and threw the towel in. However, I couln't get any power to the van from the car in any sockets, and tried with ignition on and off.

I will take a pic of the said extension lead so see what you think. It would be really handy to use it as I sometime forget to check the battery every day when away for a long period on a rally or even sometimes we get back from a day out somewhere late in the afternoon, it's getting dark - to find one of the children (OK, maybe me) has left something on and we have a flat leisure battery. The battery on the defender is quite hefty so could easily cope with a light on or two until we retire for the evening without causing any issues.

Will hopefully post picture later.

Thanks again.

 

[twindaddy]

Empty post (likely not intentional - probably an Internet Explorer issue!)

 

[twindaddy]

Excellent, I have got the pictures on (thanks Parksy)

As you can, the left picture is the socket which I would plug the caravan lean into, the socket goes into the car electrics. So, am I right in thinking I need to change the plug end for a 13pin and establish which 2 pins need to be wired in on the new 13pin plug??

Thanks
TD

 

[colin-yorkshire1]

hi, TD, in essence yes that is exactly what is needed, using pins 9 positive and pin 13 earth, look here for diagram http://uk-trailer-parts.co.uk/wiring-a-13-pin-euro-plug
with the caravan grey plug inserted into the extension socket, it should then work ok.

by the way and as an aside I know why it would not work before, remember my last post talked about pre and post 1998 wiring ??
well the extension shown in your photos is using pins 2 positive and 3 earth, assuming that the previous owner used the extension? and given the van is a 1996 it will be wired up to the earlier standard yes? however the tails you use will be post 1998 and therfore pin 2 is not used, as it was switched to pin 4, on the grey plug, so no power to the van,
fitting a 13pin plug on the end of the extension and using pin 9 as positive and 13 as earth this will energise the pin 2 configuration of the lead and the van, let us know how it goes,
colin

 

[twindaddy]

hi, TD, in essence yes that is exactly what is needed, using pins 9 positive and pin 13 earth, look here for diagram http://uk-trailer-parts.co.uk/wiring-a-13-pin-euro-plug
with the caravan grey plug inserted into the extension socket, it should then work ok.

by the way and as an aside I know why it would not work before, remember my last post talked about pre and post 1998 wiring ??
well the extension shown in your photos is using pins 2 positive and 3 earth, assuming that the previous owner used the extension? and given the van is a 1996 it will be wired up to the earlier standard yes? however the tails you use will be post 1998 and therfore pin 2 is not used, as it was switched to pin 4, on the grey plug, so no power to the van,
fitting a 13pin plug on the end of the extension and using pin 9 as positive and 13 as earth this will energise the pin 2 configuration of the lead and the van, let us know how it goes,
colin

Thanks, that makes perfect sense and I think I can do that. Do you think I will need to find a 13pin plug that only has the pins inserted I need or will be safe for all pins to be present but only 9 and 13 wired into 2&3 at the other end of the lead?

Thanks
TD

 

[colin-yorkshire1]

hi TD, a standard 13pin plug will be fine just use pins 9 and 13 for the wiring it may be prudent however to make sure all the screws in the other pins in the plug are either taken out or screwed fully home, so one does not come out and cause a short circuit while in use (common sense really) I changed both the car and van to 13pin last year, but as I use other trailers that only had a 12s plug I had to use an adapter, like this one http://www.ebay.co.uk/itm/Maypole-Quality-Euro-13-Pin-Conversion-Adapter-13-to-7-Pin-Plated-Pins-/271088300252?pt=UK_Trailers_Transporters_Parts&hash=item3f1e1f30dc however it broke after a short while so I have now converted all the other trailers to 13 pin. even though only 8 of the pins are used in the plug everything works fine, so don't worry.

 

[twindaddy]

hi, TD, in essence yes that is exactly what is needed, using pins 9 positive and pin 13 earth, look here for diagram http://uk-trailer-parts.co.uk/wiring-a-13-pin-euro-plug
with the caravan grey plug inserted into the extension socket, it should then work ok.

by the way and as an aside I know why it would not work before, remember my last post talked about pre and post 1998 wiring ??
well the extension shown in your photos is using pins 2 positive and 3 earth, assuming that the previous owner used the extension? and given the van is a 1996 it will be wired up to the earlier standard yes? however the tails you use will be post 1998 and therfore pin 2 is not used, as it was switched to pin 4, on the grey plug, so no power to the van,
fitting a 13pin plug on the end of the extension and using pin 9 as positive and 13 as earth this will energise the pin 2 configuration of the lead and the van, let us know how it goes,
colin

I have changed to plug to a 13pin, live on 9 & neg on 13!

Before I put it to the test, can anyone answer the following please...
1. Am i right in saying that I would need to disconnect the leisure batt from the 'van before the lead would work?
2. If I have wired the plug incorrectly, will it damage anything or justnot work?
3.The only time I will use the lead would be if the leisure battery has lost all charge and I'm not on EHU, therefore the fridge will be on gas, would that be ok still to use the lead?
4. Just our of interest, my parents' caravan in 2001 and therefore would have post 1998 wiring, would the lead work on their caravan?

Thanks again to all
TD

 

[colin-yorkshire1]

hi TD,
please bear with me a little as this may (a,) sound a bit technical and (b,) take a little time.
I will try to answer your questions in reverse order if thats ok
4. Just our of interest, my parents' caravan in 2001 and therefore would
have post 1998 wiring, would the lead work on their caravan?
no, I doubt it because the pin configuration of their grey plug (post 1998) would be using pin 4 for the positive lead not pin 2 as the lead is set up for. on later grey plugs (post1998) pin 2 is not used as the power comes from pin 4 "the modification would not work on theirs as there are only 2pins in the socket end of the lead and the wrong one is energised for their plug" .
3.The only time I will use the lead would be if the leisure battery has
lost all charge and I'm not on EHU, therefore the fridge will be on gas,
would that be ok still to use the lead?
yes. for two reasons there is no direct electrical link between the van wiring and the fridge, "exept for the fridge light" and I doubt if a 1996 van has a fridge light, (although I could be wrong) but even if it had the small drain of a fridge bulb every time the fridge door was opened would be very small, and as the fridge was being used on gas the 12v switch would be off "as would the 240v" one. not that any of this matters anyway as the only time 12v goes to the fridge from the car is when it is being towed via a smart relay as soon as the engine stops, the power to the fridge is cut off, but this is via a different pin on the 13pin plug which you have not used on the lead.
2. If I have wired the plug incorrectly, will it damage anything or justnot work?
IMHO, it will just not work, as any other pin in the 13pin socket, "on the car" would not send any electrical current up the lead, this is because 7 of the pins are for road lights 3 are earth wires, 1 is not used and that leaves only 2 pins, perminant power pin 9 and the fridge pin 10 now assuming you will be testing the lead in daylight with all the cars electical systems and engine turned off only pin 9 would energise the lead, the only forseeable problem could be if the wires were somehow reversed, this is easy to check with a circuit tester, if you have one, a simple 12v bulb with tails will do, just to make sure that the socket on the lead has power to the right pins. after connecting the lead to the car. it would also assist in making sure there are no breaks in the connections in the lead and also the lead has power before plugging the vans grey plug into the lead.

a tester would also assist with question 1.
1. Am i right in saying that I would need to disconnect the leisure batt from the 'van before the lead would work?
this question could be very problematical because it all depends on how the van is wired up what switches do what? and the type of zig unit fitted, I do not know the schematics for your particular van, in theory it should not matter BUT, if it was me I would disconnect it, to start with and for 2 good reasons.
1. if the battery is connected an has some charge it may not be possible to know if the lead is actually working as power will be drawn from it as soon as the lights are switched on. disconnecting it eliminates this possibility,
there may be a switch in the van that switches from internal power (van battery) to external power source (the lead) but you would have to look for this if it has one, it could have a switched ZIG unit also that senses if there is an external power source instead of a switch. either way if the battery is disconnected, only the power from the lead can power the 12v system.
2. once the lead has been checked and connected, it would be a matter of seeing what works and what does not what switch does what, without the aid of the leisure battery, at this point having establish that the lead is working, with the battery still disconnected you could then use the circuit tester to see if there is any power going down the battery leads of the lesuire battery. I suspect there will not be, but however if there is it will be an indiction that the battery WILL have to be disconnected when you use the lead.
I am afraid there is still a bit of experimentation that yet still has to be done before you have all the answers just take things one step at a time in a logical manner , asking any question you like as you go along it will be worth it in the end if it extends the use of your van.
afterall if you can get the lead to work for the cost of a 13pin plug it will be a darn site cheaper than any of the alternatives on offer wish I could do the same but with having a 2005 bailey theres no chance of that,

 

[twindaddy]

IT WORKS!!!

Very happy, I crossed everything I have and went outside and disconnected the leisure battery and plugged my DIY extension lead in and hey presto, I turned the switch inside the caravan to 'van' and lights & flush all worked. I really am very happy I can do this as spending 2 weeks without EHU, i can relax knowing I can fall back onto this method if I run out of power late at night etc.

Again, thanks to all
P.S - With regards to newer vans (post 1998), this lead of course will not be suitable, but could I make a similar one to fit my parents 2001 caravan for them to use?

 

[colin-yorkshire1]

hi TD, well done mate

glad it's sorted now for the next project!!
seriously though I would still get hold of a circuit tester one of these will do, http://www.ebay.co.uk/itm/12-VOLT-DC-6V-12V-24V-CAR-VAN-AUTO-ELECTRIC-CIRCUIT-TESTER-/190784171631?pt=LH_DefaultDomain_3&hash=item2c6b9f6e6f
then after plugging in the lead you can test the ends of battery leads to see if there is any current going through them (from the lead) you may find that there is none in which case there would be no need to disconnect the van battery while using the lead.

regarding your other question providing there is a power switch inside the van like yours then it should be possible using 10amp twin core cable and a grey socket for the van end plus a plug 12s/13pin on the car end, of course the power would have to be changed to pin 4 and earth pin 3.
however if there is no habitation relay (like my bailey) it would not work as all the 12v comes from the van battery, " there is no aux wire fitted.

 

[twindaddy]

hi TD, well done mate

glad it's sorted now for the next project!!
seriously though I would still get hold of a circuit tester one of these will do, http://www.ebay.co.uk/itm/12-VOLT-DC-6V-12V-24V-CAR-VAN-AUTO-ELECTRIC-CIRCUIT-TESTER-/190784171631?pt=LH_DefaultDomain_3&hash=item2c6b9f6e6f
then after plugging in the lead you can test the ends of battery leads to see if there is any current going through them (from the lead) you may find that there is none in which case there would be no need to disconnect the van battery while using the lead.

regarding your other question providing there is a power switch inside the van like yours then it should be possible using 10amp twin core cable and a grey socket for the van end plus a plug 12s/13pin on the car end, of course the power would have to be changed to pin 4 and earth pin 3.
however if there is no habitation relay (like my bailey) it would not work as all the 12v comes from the van battery, " there is no aux wire fitted.

Yes, next project is to change some bulbs and maybe light fittings to LED (another thread already on the go) and utilise some of the LED Strips that are readily available into the awning.
With regards to the parents 'van, how do I know if it has a habitation relay? If all interiors lights work while plugged into the car as if towing but with engine off, does that mean it has habitation relay?

TD

 

[colin-yorkshire1]

With regards to the parents 'van, how do I know if it has a habitation relay? If all interiors lights work while plugged into the car as if towing but with engine off, does that mean it has habitation relay?
TD

oh yes!! probably an automatic one,

a far simpler job, just make a lead as suggested wired to the correct pins and "hey presto" job done.
wish mine was that simple as I said my van takes all it's power from the van battery this has to be connected and charged via other means (EHU, car, seperate charger, solar panal, ect) as soon as the plug goes into the car all the 12v system goes off

.
it is possible there may be a fault somewhere but seeing as how we never spend more than one night off EHU (on a stop over) and everything works fine, further investigation seems unnessesary.