wire gauge question

**megagoo** · 05-12-2006, 08:01 PM

i have a carpc setup already in my car, but i don't know the fine details since i am not the one who installed it

currently. it is installed under my passenger seat. i want to move it to the back trunk. so i have to extend the wires where it is currently installed, to the back. ok no big deal i'll go out and get some 8 gauge or so wire (i looked at the chart in the faq, i think 8 is fine for me opus 80watt power supply) and tie it in where the computer currently is.

heres the question. the gauge of wire where it currently is does not look to be that big. looks like possibly 16 gauge wire or thinner.. if its critical i can try to get under the seat and spot a marking.. so the question is: is it safe to tie in 8 gauge wire for 7 or so feet to 16 or higher gauge wire for 4 or so feet running a 90 watt computer?

im not even sure where the guy tied the power from. i think from the extra cig lighter in the armrest storage area. im not sure how to take all of that apart but if its critical, i can try and trace it

oh and does the gauge of the 12v switched line matter too much? i'd assume not since probably very minimal power runs through it, but i have not much of a clue here

thanks
eddie

**Freelander** · 05-12-2006, 08:13 PM

if you don't know how or what's installed, then you don't know if this could happen. check the wire run, and install properly.

**megagoo** · 05-12-2006, 08:41 PM

yes i'm aware of the consequences. thats why im asking

**proph** · 05-12-2006, 08:54 PM

Run a new wire from the battery to the new location. The gauge of the wire matters if it didn't they wouldn't make different gauge wires. Make sure you fuse the wire also to protect the wire.

**megagoo** · 05-12-2006, 09:00 PM

well i actually already have a line running from the battery in the trunk compartment because i have a subwoofer amp there. so that'd be the most convienent, but i dont think the usb devices and xm radio staying on all the time would be good for the car battery.

again, my question is: is it safe to tie in 8 gauge wire for 7 or so feet to 16 or higher gauge wire for 4 or so feet running a 90 watt computer?

**Freelander** · 05-12-2006, 09:33 PM

the wire is only as good as it's weakest point. therefore, there could be a problem at the 16 gague. usually people recommend 12/10 or thicker for 90 watts.

**megagoo** · 05-12-2006, 09:57 PM

ok

is it ok to power the PC direct from the battery or will usb devices drain the battery after they're shut off? i have an m1-atx. i read a few topics about it but nothing conclusive

**proph** · 05-12-2006, 10:43 PM

Relocate the unit and connect it the same way it was. You can use the same wire as your amp if you are have room for expansion ie: your amp requires 8 gauge and you have a 4 gauge running to the rear.

Here you go... http://www.the12volt.com/wiring/recwirsz.asp

**megagoo** · 05-13-2006, 12:01 AM

yea that link was the chart i mentioned. the computer is only 90 watts and the amp is only 300.. i will check the gauge of the wire going to the amp. well come to think of it, i have another 200 watt amp daisy chained on it.

so can i just do 300+200+90 = 590 and use that for the chart?

this whole time i thought it was a bad idea to power the carpc off a constant current because of the USB thing. im not sure if the m1-atx has something that cuts it off. something about the 5v rail or something. id ont know. i'll hook it up and see what happens. maybe its possible my usb devices will shut off based on the computer or power supply and not stay on constantly?

also, i will have to run the switched 12v line from the spot in the front like i said. that wire is thin also. but am i right in assuming that there is essentially no wattage on that line, and a thin gauge is ok?

and maybe im pushing my luck without getting yelled at for not searching (even though i did on the above things) but it'd be great if soemone could tell me if theres a rule against running certain wires next to eachother (e.g. running power and speaker wire together or power and ground or whatever) to prevent interference. i'd assume its power and speaker wire i guess but im so new to this stuff..

thanks
eddie