Announcement

Collapse
No announcement yet.

How Can This Be Working???

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • How Can This Be Working???

    I took out the fuse for the foglights I don't even have hooked up and stuck a red wire in the one hole for power to my rearview camera. I stuck in a black wire to the other hole and used it for the ground for the camera and it works!!! But how??? Isn't both sides of the fuse a part of the same power line?? If so then how does my camera work??

    My only assumption is that the fusebox itself is grounded and that is how it is working. Does anyone have any idea how the camera works set up like this???

  • #2
    The other side must have a path to ground, either through foglights, or some other component that is hooked up to the same fuse. You should not run it like that regardless of the reason for it working.
    "stop with the REINSTALLS, what do you think we got some lame-o installer!!!" - mitchjs
    RevFE
    My Shop

    Comment


    • #3
      Originally posted by NJSATMAN View Post
      I took out the fuse for the foglights I don't even have hooked up and stuck a red wire in the one hole for power to my rearview camera. I stuck in a black wire to the other hole and used it for the ground for the camera and it works!!! But how??? Isn't both sides of the fuse a part of the same power line?? If so then how does my camera work??

      My only assumption is that the fusebox itself is grounded and that is how it is working. Does anyone have any idea how the camera works set up like this???
      Don't mess around in the fuse box like that. You could have fried something or yourself real good if you had flipped those wires around.

      The body of the car is the negative wire for everything. In a car environment, "negative" and "ground" mean the same thing.

      Fuses go on positive wires as close to the power source as possible. This way if the casing falls off a wire and it touches the negative frame of the car, the wire doesn't burn up.

      Negative wires aren't fused. There are no negative wires in the fuse box. The fuse has two pins. One pin is going to the source of the power. The other is still positive. It is going to the device. Which was the foglights originally.

      That ground wire you are using for the camera is doing absolutely nothing right now. So how is the camera getting ground? Either it's metal case is touching metal OR it has an RCA cable attached to it right? That RCA cable also has a ground wire in it. So the camera is getting grounded through the screen's ground.
      My Nearly Complete Car:
      http://www.mp3car.com/vbulletin/show...ed-car-pc.html

      Micro Control Center... Control Your Car Across the Internet
      http://www.mp3car.com/fusion-brain/1...-internet.html

      Website: (It's a work in progress, really. All my projects have taken me from ever really developing it.)
      http://paulfurtado.com/

      Comment


      • #4
        Originally posted by PaulF View Post
        That ground wire you are using for the camera is doing absolutely nothing right now. So how is the camera getting ground? Either it's metal case is touching metal OR it has an RCA cable attached to it right? That RCA cable also has a ground wire in it. So the camera is getting grounded through the screen's ground.
        +1 for that explanation. You are probably getting ground from the mounting or the RCA cable.

        If you need power from the fusebox, use a FUSETAP from an auto parts store. Tap the side of the fuse that isn't connected to the battery/power supply. You can test this using a multimeter or a power tester with a light. That way, it gets protection from the fuse as long as the fuse is properly matched to the application.
        Originally posted by ghettocruzer
        I was gung ho on building a PC [until] just recently. However, between my new phone having internet and GPS and all...and this kit...Im starting to have trouble justfiying it haha.
        Want to:
        -Find out about the new iBug iPad install?
        -Find out about carPC's in just 5 minutes? View the Car PC 101 video

        Comment


        • #5
          I wouldn't rule out malcoms theory of a ground path through something on that fuses feed circuit either, that is still very possible too, although yeah, most likely it is grounding through the video feed at this point.
          MY NEWEST INSTALL:modded infiniti fx with big screen

          first windows carpc install........my liquid cooled LVDS screen :D

          Comment


          • #6
            To make things worse, the wire carrying power to the camera is HOT. Not warm but HOT so I immediately disconnected.

            I took the black ground wire for the camera and found a real ground in the trunk. Metal screw into metal car body. Reconnected and camera works like before BUT the wire going to the camera is still HOT.

            I thought maybe it was a 3v requirement but I double checked and the camera is 12v. What's up with the HOT wire?? Just cheap chinese equipment, still a bad ground or what???

            Comment


            • #7
              That's how lit fuses work - when the fuse blows, if the downstream side is grounded, there is 12V across the bulb/LED which is otherwise shorted out by the fuse.

              As above, the +12V side of the fuse is hot (with ACC or IGN or permanently else with a specific switch).

              The downstream side may need to be switched ON for the grounding to occur - eg, light switch to ground through the lights, fan for the fan etc. (Hence a condition for lit fuses to light - you must turn on the faulty circuit.)


              And also as above, powering from the fusebox means an unprotected circuit (though it might have an upstream master flink which for an IGN circuit is probably the main fuse LOL).


              PS - I would definitely supply a camera from its own fused battery feed. Audio systems via vehicle fuse boxes are bad enough, but cameras...! (That's from an interference/noise POV.)

              Comment


              • #8
                I've seen some cameras can get pretty damn hot in use, if the wire is getting hot then it just means that it's drawing enough amperage threw that wire to begin to tax it... upping to a larger wire can alleviate this, would be a good idea to check the actual amperage draw & then calculate the required wire GA taking the length of the run also into account which has a large effect on the gauge you should be using, & yeah, FUSE... make sure you fuse the wire
                MY NEWEST INSTALL:modded infiniti fx with big screen

                first windows carpc install........my liquid cooled LVDS screen :D

                Comment


                • #9
                  Now that I think about it....I don't really know what I am drawing off the fuse box. The fuse box has 10, 20 and 30 amp fuses running in it. I believe the foglight fuse I pulled was a 20amp fuse but there is a good chance I'm sending more than 12v to my camera, right??

                  Comment


                  • #10
                    your sending ~14v to it when it's running, but the fact that it was a 20 amp fuse doesn't matter much because your tapping before a fuse anyway, so likes been said at this point you have no protection on this circuit other than a large master fuse downstream which is not much protection really at all...

                    some cameras are ok with just battery voltage, anything from 11-14v, but some are delicate & really should get a regulated 12v...

                    if your sure that there is nothing else on that fog circuit then I'd say to reinsert the 20a fuse & then tap your power at the fuse on the OPPOSITE side of the side your seeing power without the fuse inserted, at that point the circuit you added will then be protected by that 20a fuse... 20a sounds a bit high for a camera too, if you don't want to start checking actual amperage draw then I'd say to start out with a 10a fuse there really, if the wire is thin & it's a long run then go with a heavier wire to be safe, an insulated copper wire that's heating up under upholstery can spell disaster under the right conditions...
                    MY NEWEST INSTALL:modded infiniti fx with big screen

                    first windows carpc install........my liquid cooled LVDS screen :D

                    Comment


                    • #11
                      Well... the max you will send is whatever the battery voltage is (usually up to 12.8V, or 14.4V when charging).

                      It's current draw is a separate issue - it takes what it takes (you can't "push" current into a device except by increasing its voltage).


                      PS - Sorry - I started my reply before Turbo...
                      PPS - IMO "12V" vehicle equipment should work between 8V-16V, but definitely tolerate up to 16V (non-destructively).

                      Comment


                      • #12
                        Link to the camera specs?
                        My Nearly Complete Car:
                        http://www.mp3car.com/vbulletin/show...ed-car-pc.html

                        Micro Control Center... Control Your Car Across the Internet
                        http://www.mp3car.com/fusion-brain/1...-internet.html

                        Website: (It's a work in progress, really. All my projects have taken me from ever really developing it.)
                        http://paulfurtado.com/

                        Comment


                        • #13
                          Now that I think about it.......the power and ground wires seemed quite thin coming from the camera. Not very thick gauge wires at all, very skimpy. They are like 1/4 the size of the wire I brought out to connect them to the fuse box.

                          Maybe I'll just replace the wires going to the camera with the thicker gauge wires I have.

                          Comment


                          • #14
                            Originally posted by NJSATMAN View Post
                            Now that I think about it.......the power and ground wires seemed quite thin coming from the camera. Not very thick gauge wires at all, very skimpy. They are like 1/4 the size of the wire I brought out to connect them to the fuse box.

                            Maybe I'll just replace the wires going to the camera with the thicker gauge wires I have.
                            Thats not it dude. If the issue was the small wires, then the small wires would be the only part that was hot.

                            Theres no chance the the camera itself is drawing enough power to make wires hot. Something is wrong.

                            Do you have link to the specs?
                            My Nearly Complete Car:
                            http://www.mp3car.com/vbulletin/show...ed-car-pc.html

                            Micro Control Center... Control Your Car Across the Internet
                            http://www.mp3car.com/fusion-brain/1...-internet.html

                            Website: (It's a work in progress, really. All my projects have taken me from ever really developing it.)
                            http://paulfurtado.com/

                            Comment


                            • #15
                              this was the camera he had previously linked to-- i assume they are one and the same:
                              http://cgi.ebay.com/ebaymotors/ws/eB...m=260612140542

                              it is claimed to take only 90ma of power, and that wire should be fine for that.

                              i have been installing, and servicing cameras of many types for the last 3 years-- many with wires as thick as you have on that camera, and cannot say that i have ever come across any where the wiring going to them is extremely hot, or has gotten to a point that would indicate failure of the wire from heat.

                              as paul said, there is something seriously wrong with the way that the camera is getting power..
                              My OLD 2001 Mitsubishi Eclipse GT:
                              "The Project That Never Ended, until it did"


                              next project? subaru brz
                              carpc undecided

                              Comment

                              Working...
                              X