Permanent 12V supply to Power Socket

[DV52]

Eskys are for use on hot days so kind of ruins that argument.

You shouldn't be running a fridge of one of those circuits anyway as the current draw is mostly too high for the gauge of wire installed at factory.

I had an 8 Gauge wire running to the rear of my vehicle to run the 60L fridge I ran.

Always remembering that smart things in vehicles have to be engineered to cater for the lowest common denominator.

Hillbilly: As you can see from the pic in my tweak, the protecting element in the circuit is a 20Amp fuse. Whilst the same fuse appears to be used for both the in-cabin and hatch boot power sockets, I would think that the capacity of all of the upstream components (i.e. wiring, connectors, relay contacts etc.) in the ciggy lighter circuit would be rated at 20 Amps.

Assuming a fully charged battery with a nominal voltage of 14V, this means that an Esky attached to the power outlet could draw up to 280 Watts (or there abouts) and still not trip the fuse. I agree that this calculation assumes ideal conditions (i.e no voltage drop at the power socket outlet and ideal fuse characteristics), but it gives an indication of the permissible power-draw from this circuit. Personally, I'm not sure that I would be comfortable running this type of load in the boot of my car whilst the vehicle was left unattended and with the engine switched-off for any length of time. But, perhaps I'm being too conservative

[wai]

Skoda Octavia has permanently powered lighter socket (drives me insane). Kind of blows your argument out of the water

So did my Caddy until I switched its supply to the ignition on circuit.

I approached the ACCC and Department of Infrastructure and Transport, and they were surprised given that the Polo were recalled around 2009 for just this. They had no interest in it now as it had been removed as an ADR after manufacturers had all agreed to have the cigarette lighter socket only active with the key in the ignition on, or accessory position.

But manufacturers do some absolutely stupid things. On some models, the cigarette lighter socket is on the horizontal part of the general tray where people are known to store loose change. A coin can drop into it and short the circuit. It might not blow the fuse, but can cause heat and a fire because it is close to impossible to get a coin out without dismantling the console.

Then look at the design of the high level brake light on the Caddy that is guaranteed to crack.

So, just because a manufacturer does something does not make it right.

[DV52]

. On some models, the cigarette lighter socket is on the horizontal part of the general tray where people are known to store loose change. A coin can drop into it and short the circuit. It might not blow the fuse, but can cause heat and a fire because it is close to impossible to get a coin out without dismantling the console

wai: I've never seen what happens when a coin is dropped into the ciggy lighter socket. But I would have thought that it would be an entirely unspectacular event given the conductivity of a metal coin (particularly if the coin has any silver, or copper in it)! Can't imagine why the element in the 20Amp fuse wouldn't disintegrate immediately given the low internal impedance of a lead acid battery. I agree though that things would get mighty interesting if this didn't happen - but why wouldn't it happen?

As for getting the coin out after things settled down, why wouldn't you put a dob of "blue-tack", or superglue on a nail, or pencil and simply lift the coin out? Depending on how the coin has fallen, it might even be possible to use a pair of long-nose pliers or tweezers to grab that little sucker - especially if you wanted to spend the coin later!

[Hillbilly]

Hillbilly: As you can see from the pic in my tweak, the protecting element in the circuit is a 20Amp fuse. Whilst the same fuse appears to be used for both the in-cabin and hatch boot power sockets, I would think that the capacity of all of the upstream components (i.e. wiring, connectors, relay contacts etc.) in the ciggy lighter circuit would be rated at 20 Amps.

Assuming a fully charged battery with a nominal voltage of 14V, this means that an Esky attached to the power outlet could draw up to 280 Watts (or there abouts) and still not trip the fuse. I agree that this calculation assumes ideal conditions (i.e no voltage drop at the power socket outlet and ideal fuse characteristics), but it gives an indication of the permissible power-draw from this circuit. Personally, I'm not sure that I would be comfortable running this type of load in the boot of my car whilst the vehicle was left unattended and with the engine switched-off for any length of time. But, perhaps I'm being too conservative

You missed the point entirely.

The wiring if its too light can heat up and cause problems and also will cause voltage drop because of it being undersize.
An 8 gauge wire will do neither so is safe.

I ran a 60L Waeco fridge in my Landcruiser directly off the Aux battery through a RAPS 12 for a year with no troubles.


Off topic so I wont bother any more My eyes are getting tired

[brad]

So, just because a manufacturer does something does not make it right.

I didn't say it was right.

You quoted the rules & regs. I gave an example of what reality was. The reality affects people/me more immediately than the rules & regs.

I work in an environment where there are written policies & procedures for almost everything. This doesn't necessarily mean that reality mirrors the paperwork.

[DV52]

You missed the point entirely.

The wiring if its too light can heat up and cause problems and also will cause voltage drop because of it being undersize.
An 8 gauge wire will do neither so is safe.

Off topic so I wont bother any more My eyes are getting tired

Hillbilly: Sorry for missing your point. Clearly I haven't been sufficiently articulate in my explanation - for which I apologise again.

I am aware of the problems that can ensue from undersized wiring (i.e. heating that results from I^2 R losses where the cross section of the conductor is too small and Volt drop at the point of common coupling). However, my assertion (which I didn't make with adequate clarity in my previous explanation) is that all the downstream components in the ciggy circuit are matched to the value of the protective fuse.

This means that VW's choice of wire gauge and connector size and every other element downstream of the fuse is purposely chosen to carry up to 20 Amps ( this being the long term carrying capacity). Sure there will be some heating of the conductor wire at 20Amps, but if the conductor is suitably sized (as it surely must be in the Golf) this is perfectly OK and the integrity of the covering insulation on the wire is not compromised at this load.

As you probably already know, determining the rating of a gauge of wire is far from a simple thing. I haven't looked at the gauge of wire that is used in the ciggy circuit, but a quick glance at my (very, very) old text books (i.e. Data for Engineers: Radio, Electronics, Computer and Communications) suggests that the current carrying capacity of an 8 AWG conductor is around 46 Amps in an enclosed space (73 Amps in free air). At this rating, and assuming that you retained the 20Amp fuse, I have to agree that the circuit would run much cooler. But without seeking to be antagonistic, I doubt whether it would be any safer- because the original wiring is already "safe" from a standards perspective!

Again, thank you for letting me expand on my previously badly written explanation and I hope that your tired eyes are fully rested.

[The_Hawk]

My 2010 T5GP has a cigarette lighter in the front (next to the ashtray!) and it stays powered all the time.
There is also a removable ash try in the rear although the 12V socket there is only for power... haven't tested if that has permanent power or not since we rarely use it.

When I added in a dash cam I had to find and wire in some new switched power (which was a minor inconvenience) vs when I added a hard wired phone dock in the Golf I just used the already switched supply to the "lighter" circuit.


Those wacky Germans seems to make strange decisions at times. Is this because it's a "commercial vehicle"? Or for some other strange reasoning?? Has it changed in later models? Who knows.

[DV52]

Those wacky Germans seems to make strange decisions at times. Is this because it's a "commercial vehicle"? Or for some other strange reasoning?? Has it changed in later models? Who knows.

Hawk: I normally think of the good Burghers in Germany that design VWs in many ways, but oddly, never as "Wacky" or Zany, or Madcap, or Funny - don't know why. Maybe it's a stereotyping thing! But I do agree that there appears to be no rhyme-or-reason for their ciggy circuit decisions (and surely this must be one of the BIG decisions in the design of any car)!

Perhaps the answer has to do with whether the car is supplied with an actual ciggy lighter. That is, if a real ciggy lighter comes with the car, the circuit has a permanent 12 Volt supply - thereby allowing those with the habit to light-up any time. Otherwise, those cars that come with the blank black plastic plug, are wired through the ignition switch. How's that for a theory?

[Matty4]

I know this is a bit of a thread mine, but does anyone know if this is possible on a MK5? My daughter has her dashcam plugged into the 12v outlet in the front and it's constant but I want to change it to ignition only.
Cheers.

[Hillbilly]

I know this is a bit of a thread mine, but does anyone know if this is possible on a MK5? My daughter has her dashcam plugged into the 12v outlet in the front and it's constant but I want to change it to ignition only.
Cheers.

Buy an addafuse and fit in an ACC fuse in the fuseblock Put 5amp fuse in the top slot and away you go Have done several like that and all work perfectly I did the Passat differently as I used fuses from Jaycar with a wire already soldered on and fitted them in spare fuse slots that had power to them. You just wire a ciggy socket onto the wire off the fuse and an earth and plug the camera in Best to do it that way as some are only 5 v and have a stepdown V regulator in the plug. An hours work well spent and much neater than wires hanging down like you see all the time. Cant see any wires with my two except right at the cameras