How far can I extend the molex?

jnorion · 10-10-2006, 10:14 AM

I have my computer and power supply at the back of my trunk, about as far from the monitor as is possible in the car. I was planning to power the monitor, and possibly an IDE dvd drive, off the power supply from the computer to get an easy, clean source of power. But I'm worried about the voltage drop over that distance. I would need 12-15 feet of wire to do this... is the power supply strong enough? The screen uses less than 1 amp @ 12 volts so it doesn't need much.

If it makes any difference, I'm using a desktop power supply (running of an inverter) rated at 145W.

Wiredwrx · 10-10-2006, 10:54 AM

Quote: Originally Posted by jnorion

I have my computer and power supply at the back of my trunk, about as far from the monitor as is possible in the car. I was planning to power the monitor, and possibly an IDE dvd drive, off the power supply from the computer to get an easy, clean source of power. But I'm worried about the voltage drop over that distance. I would need 12-15 feet of wire to do this... is the power supply strong enough? The screen uses less than 1 amp @ 12 volts so it doesn't need much.

If it makes any difference, I'm using a desktop power supply (running of an inverter) rated at 145W.

A search of the forum would reveal that people do this all the time. It is not wether the ps is "strong enough" but wether the cable/wire used is thick enough, but, since the screen probably uses less than an amp of power, the wire need not be very thick. Read in the FAQs about wire gauges and amperage.

Michael

vortechs2k · 10-10-2006, 03:08 PM

Those connectors probably use 18 or 20 AWG wire. The resistance of 20AWG (and this varies slightly depending on type) is .01015 Ohm/ft. At 15 ft you're looking at .152 Ohms, and at 1A of current, you're looking at A .15V drop. I wouldn't worry about a small drop like that. But, if you do, you can always step up to 18 or 16 AWG.

jnorion · 10-11-2006, 12:10 AM

Quote: Originally Posted by Wiredwrx

A search of the forum would reveal that people do this all the time. It is not wether the ps is "strong enough" but wether the cable/wire used is thick enough, but, since the screen probably uses less than an amp of power, the wire need not be very thick. Read in the FAQs about wire gauges and amperage.

Michael

I searched around a bunch, I swear there was nothing.

Apparently searching when I'm half asleep is not a good idea.

Yes, you're correct about the power draw, according to the box the screen uses approximately .5 amps.

Thanks!

vortechs2k · 10-13-2006, 09:03 AM

Quote: Originally Posted by jnorion

I searched around a bunch, I swear there was nothing.

Apparently searching when I'm half asleep is not a good idea.

Yes, you're correct about the power draw, according to the box the screen uses approximately .5 amps.

Thanks!

http://www.powerstream.com/Wire_Size.htm

Try the link above. It shows the wire gauges and recommended maximum current values.