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Help!! Wiring car!!

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  • Help!! Wiring car!!

    OK, so I finially got ALL my stuff together, ready to be thrown into the car. But now comes the tricky part, the install. What I need to figure out is, what size power wires I need to run, and all where I need to put fuses. I am kind of confused about the fuses, from reading it seems like everything needs a fuse on it! This is my first ever install. So I drew up a quick map of my system, to clearly illustrate what's going on. (i know it's ugly, but it works

    The two amps are 350w x 1, and ~100w x 2.

    Inverter is 300w

    DBLK = distro. block

    Basicly I need to know what size wire to use to the d-block, then into the amps. Also, what wire to use for the main relay power, then the size into the inverter. I know the remote wire is small, like 18guage. Also, every place I need a fuse, don't want anything broken if somthing shorts

    I didn't draw in ground wires, but I know they are there

    Thanks for all the help!!!

  • #2
    you do the wires and fuses by how many amps go into what your wiring.. amps are usually like 10 guage with like a 30-40 amp fuse. I used 12 guage for my 360 watt inverter with a 30 amp fuse on that line.

    btw.. your picture won't load.
    '98 Explorer Sport (down atm)
    AMD 800mhz 192megs RAM 60gig hard drive 9 inch widescreen VGA
    80% done


    • #3
      Cut and paste this link for the picture:

      Old Systems retired due to new car
      New system at design/prototype stage on BeagleBoard.


      • #4
        300 watt amp and a 100 watt? You can easily do a 4 gauge from your battery to your back, use a distribution block and split the line for your amps. the ground, triggers/remote can all be the same. and fuse? well find out how many amps both your amps will draw... then there you go.

        And inverter, are we talking about a dc-ac inverter? Just plug that into your cig lighter.
        Mine needs to be updated.


        • #5
          the problem with plugging it into your cd lighter is the thin wire going up to it.. that can produce noise plus you have that wire coming from your dash. Run it off the battery.
          '98 Explorer Sport
 (down atm)
          AMD 800mhz 192megs RAM 60gig hard drive 9 inch widescreen VGA
          80% done


          • #6
            You might want to consider running the inverter/relay off of the distribution block, as well. Then if you use a fused distribution block you'd only have one battery connection and one inline fuse holder to contend with.

            The power draw and distance will determine the wire size that you need. Follow this link for more info:


            Take a look at the fuse ratings on your power amps and add them up.

            As for the inverter, if it's fully loaded and 100% efficient it should draw about 30 amps. In reality it's probably about 85% efficient, so figure about 35 amps.

            As for the power cable, try to get something that's flexible and easy to work with. I've used "Amp King" wire from Parts Express, and "Monster Cable" from a local car stereo shop. Both are really good. The main difference, between the two, is the price.


            • #7
              OK, well the wire comming off the relay for the inverter will be much larger then the amp's remote wire, can I just solder them all directly to the contact on the relay? Or should I use a distribution block there as well?

              And what's another image uploader to use, obviously forumisdown doesn't work with this forum..


              • #8
                Soldering should be fine.


                • #9
                  Allright, last question! I looked at the fuses on my amps, one has a 20a fuse, the other is dual 20a fuses. Does that make the toatal amperage on the 2nd amp 40a, or is the formula different? Then add the 35a inverter, so we are looking at ~95a draw on the main power line? Is that correct?

                  BTW: thanks for that table, it helped alot!!


                  • #10
                    Sounds about right. If you have your stereo cranked up all the way and the inverter fully loaded it'll draw, at the most, 95 amps.

                    The chart from the faq does seem kind of conservative.

                    Here are a couple of others:
                    From Crutchfield
                    Another One

                    Figure about 2-4 gauge wire from the battery to the distribution block, depending on which chart you believe, and accounting for distance from the battery. Then, coming out of the distribution block the wire can be considerably smaller (probably 8 - 10 guage). Just be sure get a fused distribution block, otherwise you'd be stuck using inline fuseholders on each wire coming out of the distribution block.


                    • #11
                      Great! Thanks again!


                      • #12
                        HA, well done bh76. But why do you have both amps connected to that purple wire for the inverter? I am assuming that purple wire from the relay to the inverter is the 12v+.

                        Everything should be grounded to a comment point. One of the dedicated spots on your car.
                        Mine needs to be updated.


                        • #13
                          Looks like I forgot to label the wires. The blue wire is the remote turn on lead coming out of the head unit. The purple wire serves the same purpose, except that it's coming out of the relay and can provide enough current for the inverter.

                          Unrealer33's diagram used the output on the relay to turn on the amps, so I kept it the same on the diagram that I drew.