Question about Cigarette Lighter for power.

ninvertigo · 09-07-2007, 12:32 AM

Hello everyone. I am sure this has been covered, but after a few hours of searching I have yet to come up with a definite answer.

Equipment:
Intel Shelton MicroITX motherboard.
Molex procase 90watt DC-DC Power supply unit.
Lilliput 7inch LCD touch screen

I have a 2007 Chevy Cobalt that just happens to have a perfect amount of space below the DIN units to the left of the gear shifter under the dash to fit the mother board, with power supply on one side, and Compact Flash to IDE on other other. The cup holders can be popped out without tools, and I have easy access to spare USB ports, and can swap the flash cards for other OS boots.

Now for my question, I have two cigarette lighter spots. One the actual cigarette lighter, the other is a 12volt AUX power connector. The light had spazzed out on me previously and doesnt seem to function all that great. The AUX works fine however(for charging my cell phone and Ipod). The AUX connector has two wires(typical) and is easy access right by the PSU of the main board.

Can I splice into that cigarette lighter and run a wire directly to the PSU on the computer, as well as to still use the actual socket for the LCD screen. Does a cigarette lighter push out 12volts, and at what amperage? Most likely 14.4 volts and 15amps would be my guess, but im scared to wire them up directly like that as I do not want any crazy sparks or overloads going to or from the computer. Will pushing 14.4 volts on a 12v dc input powersupply hurt it if this is the case? And the load from the LCD screen and the PC should be ok running on the same circuit correct(with nothing else running at the time).

So to recap. Can I splice a wire from the AUX 12v power socket directly to my PSU for my carputer, and will it work with both it and the cigarette lighter adapter plugged into the lcd screen at the same time?

ASCII illustration...

LCD Screen cigarette lighter adapter--------| |
PC PSU ---------------------------------> + - AUX ---- line to fuse box ---

Thanks in advance,
Scott

DarquePervert · 09-07-2007, 07:18 AM

You can physically wire the PC to the cig lighter, but I wouldn't recommend it.
For safety and reliability reasons, you should run a line directly back to the battery to power the computer.

Splicing in the the screen's power to the cig lighter shouldn't be a problem, however.

ninvertigo · 09-09-2007, 03:34 AM

Thanks for your input.
What I ended up doing was cutting a couple of holes in the plastic around the center console under the din radio unit and hvac controls. I placed two switches. A momentary push button for the pc's power, aswell as a rocker switch for the 12volt power. I ran one ground from the lighters port directly to a 1light adapter to 2 Y splitter. Next I ran a power wire from the lighters power line to the rocker switch, then to a 10amp fuse to the Y splitter. I cut the second adapter off of the Y splitter and soldered it to the pc's power supply. Then I use the adapter slot for the cigarette lighter socket power of the lcd touch screen monitor.

So now basically I throw the rocker switch to ON and my lcd screen comes on and my PC's PSU gains power... hit the push button to power on the pc and in about 15 seconds I have Centrafuse running

My only complaints at this point is the limited amount of space naturally. The fact that I have to use the AUX audio input on my factory DIN stereo. I have no idea where to mount the monitor. And at somepoint I killed the other cigarette lighter slot. No fuses are blown, and I checked it with a multi-meter... no power... *yikes*

Anyone know if this has voided the warranty on my 2007 Cobalt? I'll get some screen shots up soon to show you guys, I think this isnt a half bad installation(atleast for the mother board)

-Scott

Maheriano · 09-09-2007, 11:17 AM

Where's Toast with the image?

ninvertigo · 09-09-2007, 11:51 AM

What? Huh?
Like Roxio Toast, and the image of what?

Rob Withey · 09-09-2007, 12:00 PM

No, like this : http://www.mp3car.com/vbulletin/857325-post4.html

DarquePervert · 09-09-2007, 12:41 PM

Quote: Originally Posted by Maheriano

Where's Toast with the image?

Quote: Originally Posted by ninvertigo

What? Huh?
Like Roxio Toast, and the image of what?

Toaster is 2k1Toaster, a helpful long-time member of these forums.

The image is this one, which cartoonishly, et accurately illustrates the dangers of wiring your vehicle computer to the cigarette lighter for power:

ninvertigo · 09-09-2007, 12:58 PM

I see... well the power supply unit is drawing 60watts over some heavier gauge wire. Fused about 6 inches from the PSU, and once again at the 15amp fuse box less than 1 foot away. I have a few PSU's and I stepped it down to the lowest wattage that everyone would run at. Usually when wires are ran to the battery by me, they tend to pop and arc weld themselves to things. In another car I had a 2000watt precision power amp going to three 10inch JL sub woofers. This of course ran directly to the battery with 4 gauge wire and was inline fused about 1 foot from the battery. This seemed logical due to the amps draw... but honestly I dont understand how my pc could have enough power on the load to cause any issues. Does anyone actually have accounts of a mother board catching fire? And I have that quick power off rocker switch... so if the pc shuts down while driving for whatever reason within 3 seconds I have that entire circuit collapsed. Is this honestly not at all safe? Less than 3 feet of wire total less than 5amp's at 12-14 volts being drawn. I really do appreciate the advice, and im a tad scared, but I honestly dont see an issue.

Yr_cordoba · 09-18-2007, 09:51 PM

ninvertigo if u can would u please upload some pictures of ur project. i have the same car and i had been working in it for some time.. would finally finish it soon i hope lol