12v car wire questions

[moody07747]

ok heres the deal...i have a GPS unit for my PDA, only thing is it runs on the round car outlet...i want to just make a cord to work with my 1-30V power supply so i can run the GPS inside for setup

are the tips of these male ends always the +?

any idea if this will work or will it just fry my GPS thats cheap anyways?

 

[stevez]

You'd want to be sure that the voltage on your power supply is limited to 14 or 15 volts. I'd set it closer to 12 volts myself.

The pin is usually but not always +

Read the mfrs instructions to be sure. In the past there were autos with + ground (chassis) but I have no idea if all vehicles are - ground.

 

[Nigel Goodwin]

ok heres the deal...i have a GPS unit for my PDA, only thing is it runs on the round car outlet...i want to just make a cord to work with my 1-30V power supply so i can run the GPS inside for setup

are the tips of these male ends always the +?

any idea if this will work or will it just fry my GPS thats cheap anyways?

Use a meter and measure it!, the polarity of the lighter sockets doesn't appear to be reliable across different cars - in my experience the centre is probably more often negative than positive (all on negative earth cars). I wouldn't plug anything in without testing it first.

 

[mramos1]

Does the connector for your in-house power supply match the GPS like the one on the car adapter? If so...

Take a meter (as instructed above) to the car adapter (car not running). Put the RED lead on the tip or center pin of the connector (of course you have the meter on 20 volts DC) and the BLACK on the sleeve (outer metal normally). See if there is a minus sign in front of the voltage reading (normally not minus in the US, now make a mental note if the minus was there or not).

NOW, set the in-house power supply to 12 volts. Repeat the last paragraph on your in-house power supply with your meter. If the reading is the same (far as the minus being there or not), plug it in and go. If they do not match, flip the leads on your power supply and do the test again. If it matches the car adapter, plug it in and go.

This is the same thing Nigel told you to do with more details only because I see you called the cigarette lighter outlet (as called here in the US) the "round car outlet". Hate to see you break the GPS, and they probably have a diode in there to protect you, but just in case.

 

[moody07747]

thanks, ill test it out tomarrow

I dont really care if i break this GPS unit...im selling it and getting a new one anyways and this ones only worth $90

 

[Oznog]

The lighter socket is ALWAYS negative on the outside and positive at the tip (center). It's a standard that a huge number of appliances and power inverters depend on. The only exception I know of is if someone monkeyed with the wiring.

 

[Nigel Goodwin]

The lighter socket is ALWAYS negative on the outside and positive at the tip (center).

There goes a man with a blown fuse and a short circuit protection diode - if he's LUCKY! :lol:

 

[audioguru]

The lighter socket is ALWAYS negative on the outside and positive at the tip (center). It's a standard that a huge number of appliances and power inverters depend on. The only exception I know of is if someone monkeyed with the wiring.

They have some stoned, drunk monkeys working on the car manufacturer's production line. Just hope that your car wasn't built on a Monday morning.

 

[hyedenny]

thanks, ill test it out tomarrow
I dont really care if i break this GPS unit...im selling it

There goes a man who doesnt care about ripping someone off! Nor can he spell "tomorrow."

Negative IS always on the outside... At least in the past 30 years or so with negative-ground cars and airplanes.

 

[Nigel Goodwin]

Negative IS always on the outside... At least in the past 30 years or so with negative-ground cars and airplanes.

Can't comment on airplanes, but over the last 30 years I've seen LOADS of sockets in caravans and cars wired the other way - always test with a meter, it only takes seconds - and if you don't have a meter, what are you doing here?.

 

[Russlk]

I don't know of any vehicle with positive ground in the past 20 years at least. All cars built in the US have the tip positive and the outside negative (ground).

 

[Klaus]

Yes but Nigel is in ENGLAND, where they do things differently :roll:
I know, as Australia was once an English colony and we still suffer the oddities of it :lol:

Can't say that I have ever come across a reverse wired cig lighter socket but anything is possible. When you think of it, the cig lighter that originally was used with these sockets did not mind which polarity it got to heat the element.

What I can't understand is why these abominal sockets carry on to this very day and are being used for things thery were never designed for. The original use only required short term contact, to connect something like a GPS where a reliable connection is required as the car bounces about is asking for too much.
Klaus

 

[Nigel Goodwin]

I don't know of any vehicle with positive ground in the past 20 years at least. All cars built in the US have the tip positive and the outside negative (ground).

I don't know of any, at all recent, positive earth vehicles either, but we're not talking about the earth polarity of the car - only of the lighter socket, and the outer ISN'T grounded to the chassis, only connected via a wire, so it can be easily connected either way.

We sell portable TV's to people to use in cars or caravans, and we get quite large numbers returned as 'not working', and they have been connected the wrong way round. At this point we ask for them to bring the car (or caravan) in and we test it, in almost all cases the centre pin is negative!.

Admittedly this is a biased sample, because the ones that are wired positive centre don't come back, but portable TV's is only a VERY small part of our business - and I see no reason to assume it's not a representative sample?.

Saying that "All cars built in the US have the tip positive" is rather a sweeping statement!, have YOU personally checked all of them?.

So, I'll repeat again! - DON'T BLINDLY ASSUME THE CENTRE IS POSITIVE, CHECK WITH A METER!.

 

[Russlk]

I have only checked Ford, GM, Chrysler, Toyota, Subaru, Lancia, Jeep. Have not checked any British cars!

 

[hyedenny]

BMW, Mercedes, Toyota, Nissan/Datsun here.

 

[Nigel Goodwin]

Have not checked any British cars!

What British cars?.

 

[Dan East]

If any cars here in the US had anything but tip positive in the cigarette lighter the manufacturer would be sued out of existence, after millions of dollars worth of electronics were damaged.

Dan East

 

[AllVol]

And many Americans cars are now coming off the line without cigarette lighters. The lighter and plug-in ashtray is becoming an option.

 

[hyedenny]

Ya, they call cigarette lighters "power ports" now.... If auto manufacturers could just get smokers to suck on power lines instead of cigarettes, or get them to use their ashtrays instead of the highways, theyd have something worthwhile!

 

[Dan East]

Our 2005 van has four "power ports", spread from one end to the other. Usually three of them are being used, and we've needed more than four on a few occasions.

Dan East