[David]

Just a quick question.

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing pins?

Cheers


Dave R

--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[Dave Liquorice[_2_]]

On 7 Dec 2016 11:23:04 GMT, David wrote:

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing
pins?

Isn't the caravan supply relay controlled only live with the engine
running?

--
Cheers
Dave.

[David]

On Wed, 07 Dec 2016 11:37:54 +0000, Dave Liquorice wrote:

On 7 Dec 2016 11:23:04 GMT, David wrote:

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing
pins?

Isn't the caravan supply relay controlled only live with the engine
running?

Yes (Pin 10), but it occurs to me that you could pick up the battery
charging, interior lights etc. circuit on Pin 9 (always on) and link that
to Pin 10 with an ignition-driven relay. This would give you ignition
controlled power on Pin 10 but I am assuming that there isn't enough
capacity in Pin 9 to support battery charging, internal lights and the
fridge (else why have a separate circuit?).

Which led me to wonder how to easily check if the correct installation
(separate fused feed from the battery) had been wired in.


According to the Caravan Club http://www.caravanclub.co.uk/media/1022790/
towbar-wiring-mo.pdf Pin 9 and Pin 10 should both be of 21.5A capacity.


The main issue seems to be that modern large fridge/freezers require a lot
of power to operate and so require their own dedicated supply (as large as
possible).

Anyway, any non-destructive method of checking that Pin 9 and Pin 10 have
independent 21.5A supplies?


Cheers


Dave R



--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[Dave Plowman (News)]

In article ,
David wrote:
Just a quick question.

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing
pins?

I'd say most cars probably wouldn't have an ignition switched supply
readily available at the rear of the car. So unless provided by the car
maker for this job would have to be added. And hopefully done correctly.

--
*What do you call a dinosaur with an extensive vocabulary? A thesaurus.*

Dave Plowman London SW
To e-mail, change noise into sound.

[Davey]

On 7 Dec 2016 13:54:41 GMT
David wrote:

According to the Caravan Club
http://www.caravanclub.co.uk/media/1022790/ towbar-wiring-mo.pdf
Pin 9 and Pin 10 should both be of 21.5A capacity.


The main issue seems to be that modern large fridge/freezers require
a lot of power to operate and so require their own dedicated supply
(as large as possible).

Maybe this pin should be considered and used as a battery charging
supply for the dedicated battery in the caravan?

--
Davey.

[Harry Bloomfield[_3_]]

David explained :
Anyway, any non-destructive methodod of checking that Pin 9 and Pin 10 have
independent 21.5A supplies?

The big problem due to it being 12v, is voltage drop - as it is a long
way from the front of the car to the rear.

One way to test it is adequate is to apply a load, measure the drop end
to end, then from that - calculate the cable size.

Commonly, a single always live feed is used from the battery, to the
boot area. Then a voltage activated split charge relay is installed in
the boot. Problems occur when that single feed is not hadequetely sized
and the relay clicks in and out constantly. Voltage rises, relay makes,
load then causes volts drop so relay opens, voltage rises... and so on.

I always install 6mm or 2x 4mm for the common feed to the rear.

[Harry Bloomfield[_3_]]

It happens that Dave Plowman (News) formulated :
I'd say most cars probably wouldn't have an ignition switched supply
readily available at the rear of the car. So unless provided by the car
maker for this job would have to be added. And hopefully done correctly.

Most/many professional installers do not understand the need to rate
the cable size for both current capacity and to avoid voltage drop.

[Tim Watts[_3_]]

On 07/12/16 15:07, Harry Bloomfield wrote:
David explained :
Anyway, any non-destructive methodod of checking that Pin 9 and Pin 10
have
independent 21.5A supplies?

The big problem due to it being 12v, is voltage drop - as it is a long
way from the front of the car to the rear.

One way to test it is adequate is to apply a load, measure the drop end
to end, then from that - calculate the cable size.

Commonly, a single always live feed is used from the battery, to the
boot area. Then a voltage activated split charge relay is installed in
the boot. Problems occur when that single feed is not hadequetely sized
and the relay clicks in and out constantly. Voltage rises, relay makes,
load then causes volts drop so relay opens, voltage rises... and so on.

I always install 6mm or 2x 4mm for the common feed to the rear.

When we did this decades ago, we shoved a schottky diode in series with
a fused wire direct from the battery and used this as the perm live to
the caravan with a socket in the boot to charge my mum's disability scooter.

With 0.6V forward voltage drop, this worked fine - caravan's leisure
battery seemed to charge OK when the car was moving, as did the scooter.

To protect the car from being flattened when the caravan was hooked up
but being lived in (and the leisure battery running down), I made a
voltage sensitive trip for the caravan that just cut all power when the
voltage went below an adjustable amount.

[Harry Bloomfield[_3_]]

Tim Watts formulated the question :
When we did this decades ago, we shoved a schottky diode in series with a
fused wire direct from the battery and used this as the perm live to the
caravan with a socket in the boot to charge my mum's disability scooter.

With 0.6V forward voltage drop, this worked fine - caravan's leisure battery
seemed to charge OK when the car was moving, as did the scooter.

0.6V is a lot of voltage lost, when the charge voltage might only be
14v. I used a diode on one of my early caravans and gave it up as a
really bad idea.

[Tim Watts[_3_]]

On 07/12/16 16:22, Harry Bloomfield wrote:
Tim Watts formulated the question :
When we did this decades ago, we shoved a schottky diode in series
with a fused wire direct from the battery and used this as the perm
live to the caravan with a socket in the boot to charge my mum's
disability scooter.

With 0.6V forward voltage drop, this worked fine - caravan's leisure
battery seemed to charge OK when the car was moving, as did the scooter.

0.6V is a lot of voltage lost, when the charge voltage might only be
14v. I used a diode on one of my early caravans and gave it up as a
really bad idea.

And yet it worked for us... For years.

Our Fiat 131 would top at at 14.4 and we ran a 20A rated wire direct to
the battery for this.

[David]

On Wed, 07 Dec 2016 14:29:08 +0000, Davey wrote:

On 7 Dec 2016 13:54:41 GMT David wrote:

According to the Caravan Club
http://www.caravanclub.co.uk/media/1022790/ towbar-wiring-mo.pdf Pin
9 and Pin 10 should both be of 21.5A capacity.


The main issue seems to be that modern large fridge/freezers require a
lot of power to operate and so require their own dedicated supply (as
large as possible).

Maybe this pin should be considered and used as a battery charging
supply for the dedicated battery in the caravan?

?

Pin 9 is for battery charging and always on.

Pin 10 is for the fridge and switched by the ignition.

Both circuits are needed, must be fully functional and separate. Pin 9
also powers the ATC Trailer Control as well as charging the battery and
powering the internal lights.

If there is barely enough power to run the fridge/freezer it isn't going
to be able to power all the other stuff as well.

Cheers


Dave R



--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[Capitol]

Harry Bloomfield wrote:
Tim Watts formulated the question :
When we did this decades ago, we shoved a schottky diode in series
with a fused wire direct from the battery and used this as the perm
live to the caravan with a socket in the boot to charge my mum's
disability scooter.

With 0.6V forward voltage drop, this worked fine - caravan's leisure
battery seemed to charge OK when the car was moving, as did the scooter.

0.6V is a lot of voltage lost, when the charge voltage might only be
14v. I used a diode on one of my early caravans and gave it up as a
really bad idea.

He used a Schottky diode, much lower Vf.

[Capitol]

David wrote:
Just a quick question.

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing pins?

Cheers


Dave R


Check for lack of continuity between the pins.

[bert[_7_]]

In article , "Dave Plowman (News)"
writes
In article ,
David wrote:
Just a quick question.

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing
pins?

I'd say most cars probably wouldn't have an ignition switched supply
readily available at the rear of the car. So unless provided by the car
maker for this job would have to be added. And hopefully done correctly.

Any car which offers an approved towbar will be equipped with a plug in
socket for the wiring loom for a caravan conforming to EU standards
(except it would seem from an earlier comment VW0
--
bert

[Dave Liquorice[_2_]]

On 7 Dec 2016 16:43:48 GMT, David wrote:

Pin 9 is for battery charging and always on.

Pin 10 is for the fridge and switched by the ignition.

But I'm reasonably sure pin 10 shouldn't become live unless the
engine is running, ie the alternator turning. So ignition on,
ignition light not lit.

So if you have volts on pin 10 with ignition on, engine not running
it's not being switched correctly and this may weel be just a link
for pin 9.

--
Cheers
Dave.

[Harry Bloomfield[_3_]]

David wrote :
Pin 9 is for battery charging and always on.

I am not familiar with the 13 pin, but the above would seem to be
wrong.

If pin 9 is always on, that means that with a flat battery on the tow
vehicle, it will back feed from the trailer when any attempt is made to
crank the engine.

One the 7S the battery charge pin is only connected when the primary
battery is being charged, to avoid such problems.

[David]

On Wed, 07 Dec 2016 22:24:44 +0000, Harry Bloomfield wrote:

David wrote :
Pin 9 is for battery charging and always on.

I am not familiar with the 13 pin, but the above would seem to be wrong.

If pin 9 is always on, that means that with a flat battery on the tow
vehicle, it will back feed from the trailer when any attempt is made to
crank the engine.

One the 7S the battery charge pin is only connected when the primary
battery is being charged, to avoid such problems.

AFAIK there is ECU protection which cuts the current if the vehicle
battery goes below a certain voltage.



--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[David]

On Wed, 07 Dec 2016 17:24:00 +0000, Capitol wrote:

David wrote:
Just a quick question.

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing
pins?

Cheers


Dave R


Check for lack of continuity between the pins.

Good point!

That should pick up the first level of bodging.



--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[bert[_7_]]

In article , David
writes
On Wed, 07 Dec 2016 17:24:00 +0000, Capitol wrote:

David wrote:
Just a quick question.

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing
pins?

Cheers


Dave R


Check for lack of continuity between the pins.

Good point!

That should pick up the first level of bodging.



This might help
https://www.google.co.uk/url?sa=i&rc...ages&cd=&cad=r
ja&uact=8&ved=0ahUKEwjIxfuVtOXQAhUFWxQKHcLXBVcQjRw IBw&url=http%3A%2F%2Fww
w.towbarandtrailercentre.com%2Fwiring-diagrams-18-w.asp&psig=AFQjCNHiMBJY
deDGM1tq9riRP6TLCPwBQw&ust=1481314363282474
--
bert

[bert[_7_]]

In article , David
writes
On Wed, 07 Dec 2016 17:24:00 +0000, Capitol wrote:

David wrote:
Just a quick question.

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing
pins?

Cheers


Dave R


Check for lack of continuity between the pins.

Good point!

That should pick up the first level of bodging.



For a full explanation
https://www.google.co.uk/url?sa=t&rc...b&cd=8&ved=0ah
UKEwiPuoCQtOXQAhUsIcAKHXsQABoQFgieATAH&url=http%3A %2F%2Fwww.caravanclub.c
o.uk%2Fmedia%2F1022790%2Ftowbar-wiring-mo.pdf&usg=AFQjCNEE2YHiO6gPjKrEOq6
I6g-y9k00wg&sig2=5NyBrX0zfos7P-DaP9pLwA&bvm=bv.140915558,d.d24&cad=rja
--
bert

[bert[_7_]]

In article , bert writes
In article , David
writes
On Wed, 07 Dec 2016 17:24:00 +0000, Capitol wrote:

David wrote:
Just a quick question.

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove that
this is a separate power supply and not just bodged from the existing
pins?

Cheers


Dave R


Check for lack of continuity between the pins.

Good point!

That should pick up the first level of bodging.



This might help
https://www.google.co.uk/url?sa=i&rc...ages&cd=&cad=r
ja&uact=8&ved=0ahUKEwjIxfuVtOXQAhUFWxQKHcLXBVcQjR wIBw&url=http%3A%2F%2Fww
w.towbarandtrailercentre.com%2Fwiring-diagrams-18-w.asp&psig=AFQjCNHiMBJY
deDGM1tq9riRP6TLCPwBQw&ust=1481314363282474
Should have mentioned that there are 3 different earths on the 13 pin
socket and each should go back to a vehicle earth and not be linked on
the socket.
--
bert

[Andy Burns[_13_]]

bert wrote:

This might help
https://www.google.co.uk/url?sa=i&rc...ages&cd=&cad=r
ja&uact=8&ved=0ahUKEwjIxfuVtOXQAhUFWxQKHcLXBVcQjRw IBw&url=http%3A%2F%2Fww
w.towbarandtrailercentre.com%2Fwiring-diagrams-18-w.asp&psig=AFQjCNHiMBJY
deDGM1tq9riRP6TLCPwBQw&ust=1481314363282474

Jesus! what's wrong with shortening stuff?

http://towbarandtrailercentre.com/wiring-diagrams-18-w.asp

[David]

On Thu, 08 Dec 2016 20:23:28 +0000, bert wrote:

In article , David
writes
On Wed, 07 Dec 2016 17:24:00 +0000, Capitol wrote:

David wrote:
Just a quick question.

With modern 13 pin connectors there is a pin for providing power to a
caravan fridge. Pin 10, ignition controlled.

As far as I can tell this is not supported by the standard wiring in
German cars until ver recently.

Is there any obvious way (apart from tracing the wiring) to prove
that this is a separate power supply and not just bodged from the
existing pins?

Cheers


Dave R


Check for lack of continuity between the pins.

Good point!

That should pick up the first level of bodging.



For a full explanation
https://www.google.co.uk/url?sa=t&rc...b&cd=8&ved=0ah
UKEwiPuoCQtOXQAhUsIcAKHXsQABoQFgieATAH&url=http%3A %2F%2Fwww.caravanclub.c
o.uk%2Fmedia%2F1022790%2Ftowbar-wiring-mo.pdf&usg=AFQjCNEE2YHiO6gPjKrEOq6
I6g-y9k00wg&sig2=5NyBrX0zfos7P-DaP9pLwA&bvm=bv.140915558,d.d24&cad=rja

A nicely obfuscated link which I posted further up thread ;-)



--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus