novice, fusebox usb circuit

Ahoy,

I'm a total 12v/electronics novice, but I'd like to fit a female USB port into my car in order to charge a GPS, PSP or any of my other USB devices. It'd be so helpful if I could run my idea by someone who knows what they're doing... :D

I appreciate any time you can give to post in reply, so I'll try and keep this succinct.

I have a 04 Model Skoda Fabia. I'd like to run a wire from the fusebox, which looks like this , (minus the red wires), using an add-a-circuit device like this, so I don't have to solder anything or deal with any wire ends at that stage.

At the other end of the wire running from this add-a-circuit I'm going to attach an in-line cigarette lighter socket like this, making the circuit more modular. From this I will connect a common 12v -> USB adapter, and from that a USB extension cable.

The USB extension cable and the 12v -> USB device is something I already have, so this isn't a problem. My question is, does my circuit make sense other than this.

I'll be plugging the add-a-circuit into the fuse for the existing cigarette lighter and using the same rating of fuse for the new circuit.

Secondly, the add-a-circuit device seems to only have one wire coming out, does the cigarette lighter adapter not require a ground or neutral? It certainly has solder tabs for one.

I'd be very grateful of any insight or help anyone can render,
Thankyou.

Domokun

Somewhat useful diagram...
Mini blade fuse gap in fusebox -> Add a circuit device -> wire behind the dashboard -> cigarette lighter adapter -> 12v/usb converter

You could simplify your setup a bunch, by simply attaching the wires from the new 12V socket to the wires from the existing cigarette lighter, making sure to get the polarity correct.

This would dispense with the "add-a-circuit" and all that stuff at the fusebox, and wouldn't overtax the wiring since the USB devices will draw a negligible amount of current.

As far as the lighter itself - some thoughts.

1. The terminology used to describe Direct Current consists partially of the same words as that describing Alternating Current for circuits with entirely different functions. A ground in an AC system does not carry current under normal conditions, but a ground in a DC system does. Also "neutral" is generally not used for automotive electrical systems.

2. Since almost all late-model cars are 12V negative ground systems, "hot" and "positive" are used interchangeably on this site, as are "ground" and "negative".

3. The add-a-circuit device is only designed to add a "hot" circuit. As I mentioned in my first paragraph, it's unnecessary to use one at all.

4. I can't see the terminals on the picture of the lighter socket that you've linked to, but the polarity of every socket I've seen has been center = positive, outside = negative.

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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two

this is totally out of line here but i was previously a domestic electrician before i got into electronics and in AC systems technically, if you think about it a neutral wire doesn't exist, why it's there? that i never figured, it's really only hot and earth as they are reffered to in ac terms, the neutal bar in any AC system's main panel at the end is earthed off, so technically a neutral bar doesn't exist.

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COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF. PSALMS 37:5

Good lord Darren someone understands the term earth on your side of the pond,  I have to stop myself using that word instead of ground and as for boot, wing, bumpers and bonnet the less said the better.  Chris,  I can't get into your blog site so it's facebook or email, Mr. domokun just hook the  RED of your cig lighter socket to red on the fusebox and the Black to any plain brown, that's permanent feed. If you want ign for the pos side, which is the centre feed on ANY cig lighter, go a BLACK/ blue at f/box or black /red at OBD ll socket, again, black to car's brown. Guys, Fabia is a VW Polo, a scaled down Golf but much better built.  Skoda were a Trabant type joke until VW took them over after Communism, now their build quality is quite superb.

Just seen the photo, that's so stupid, those leads are not properly tied in, correct access would be to go to the other side and pick up i.e. solder to those cables. Tell you what that photo even tells me it's a right hand drive, probably UK spec vehicle. Also notice the Maplin ad, you can buy them elswhere, Halfords etc prewired. Come to think of it that fusebox is identical to a Golf Mk IV

That's strange howie, I don't know why the blog isn't accessible. You're going to this URL?

I think the original poster here long ago abandoned the thread, but anyway.

So thanks to you and Wikipedia I've learned that a "wing" is a fender and a "spanner" is an ordinary wrench, but what the hell are bumpers, other than the parts at the front and rear of the car that are supposed to absorb an impact?

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C Renner's Auto Electronix
My service is cheap, quick, and good - pick any two

It's not just your blog, I just got blown off this site the next to times, I was denied access, all because my reply sl*gged off Murdochs minions at home security alaia Sky TV. But first some more although t&t will probably know them. Over here a fag is a ciggie!  We have allen bolts = hex bolts, jubilee clips = hosepipe clips, windscreen = windshield, daytime running lights? Only in Scandinavia but then we have rear fog lights. I didn't realise bumpers were the same. Now for the applied economics theme. I'm moving on Monday (no Internet till Wed night)  Phoned Sky (Direct Sat, owned by Murdoch's News International)  asked for an install, quoted me £110 for an install and £55 ($160) per month for Sat Channels and home broadband. Realised there are 2 sat ant points + cable + terrestrial  (digital) TV sockets in a single wall plug, borrowed a friend's used Sky + box (Sat tuner + TiVo), it all worked, bought the box for £40 and £10 per month  for his spare Sky vewing card (encrypted Sim card), also for $5 per month I subscribe to graboid, all the new US TV shows like 24, Gossip Girl etc well before they appear here. It pays to punt around.