I have a stereo component that is powered by a cigarette lighter adapter. (Its an MP3 player). Anyway, I would like to make the power supply a bit more permanent and out of sight. I want to just clip off the adapter and run the wires directly to a switched circuit so it only gets power when the igition is on. I havent done a ton of wiring before.. Does anyone have an easy way of doing this? How can I tell which wire is positive and which is negative when I clip off the lighter adapter??

 

you can if nothing else just use the same wires you are running your stereo on.
I would not recommend. Get a test light and you can find a constant power source or ignition power supply. Your power cord should have a white stripe on one of them, this should be positive.

 

The wire going to the center of the cigarette adapter will be the positive wire.

If you tap into the radio's power lead, make certain it's the switched one. This lead should only be 'hot' when the ignition is in the 'On' or 'Accessory' positions.

 

i once had a similar problem but decided to not try to hardwire it for one reason. In the adapter there is a fuse that will save the device from getting killed. When u cut away the adapter the device is no longer protected and could fry your mp3 player. Unless you put a fuse somewhere on the postive wire (my wires where soooo small that it would be very hard to do this) it puts the device at risk. I simply plugged the device into the cig lighter and then wired it through my dash so only the adapter was out no wire. Kinda sucks but i didnt want to have to buy a new radar detector.

My .02

Ryan



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www.350iroc-z.com

 

350iroc-z makes a good point.

Even though you connect to a switched hot wire, the fuse protecting that circuit may be inadequate for the wiring & device you're planning to use. Typically, the fuse of a circuit is rated to protect the wiring, not the device, in order to prevent a short from turning your vehicle into a big toaster.

Here's a suggestion: Find a switched hot wire as I mentioned in my earlier post. Purchase an in-line fuse holder from an electronic store. Radio Shack definitely has them. Get an appropriate fuse for the wiring or device you're going to use. The one that's already in the cigarette adapter should be rated for the wiring & device.

Don't forget that you'll need to wire in the voltage reducing circuit as well. Most of the devices you'll be planning to use won't use 12 volts, more like 3-6 volts. Keep in mind these cicuits can get hot. If the voltage adapter is adjustable, locate in a place that's easily accessible.

Another suggestion is to install an 1/8" female jack, like the one often used between the left & right speakers of your PC, to bring the circuit to a convenient location and allow you to quickly connect/disconnect the device. Make up a cable w/ a male 1/8" plug on one end and the appropriate connector for your device on the other. Watch the polarity when you make the cable.

I know this sounds like your back to the cigarette adapter, but this will be much cleaner than having that huge ugly adapter hanging out of your dash.

 

89IROC, I have a ton of those little in-line fuse-holders in my car! When in doubt, I fuse the thing! (Then I pray the fuse never blows, because they always wind up being in hard to reach spots!)


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

I have a wierd question!! Does the MP3 run off 12V or is there circuitry in the adapter to reduce the voltage for the player. I know my CD player runs off 4.5V but it plugs into the ligher socket. Just a question!!

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91 Z28 Camaro
305 TPI
700R4 with 2000 Stall and shift kit

 

Your adapter has a circuit in it to reduce the voltage.

After using it for a while, feel the adapter. It will be warm/hot. If it didn't have a voltage reducing circuit it would be at the ambient temp (unless of course the wiring in it is underrated for the current being drawn by the player).

This is why my previous post included the section on the adapter circuit/wiring.

Hope this helps ...

 

The MP3 player I have runs on 12V. It is not a portable MP3 "walkman" but more like the size of a small CD changer and I have it mounted in the trunk. It takes a standard size hard drive and had a display / control module that displays the song, etc...

 

Doesn't the fuse board supply power? Cause if it does you can buy a fuse split or something like that, (I saw one at my local Automotive store) and On TV the other day i saw a show saying you can wire something (I can't remember what they were wiring) to the fuse board. All you have to do is take a circuit tester and check for a fuse that lights up when the car is on but doesn't light up when the car is off. Run a switch off of that and voila.

Of course that all depends on whether or not you can wire it to the fuse board..

I'll need someone to correct me if i'm wrong, or if there is a similiar way and i just think it's this way.

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'86 Camaro
2.8 MPFI

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