How to Install a Rear Dash Cam?

I bought two Blueskysea B1W from this deal My intention was to run them as separate front and rear cameras. I didn't really think it through and I have no idea on how to install the rear camera. I was going to get a long usb extension cable and run it to the front cigarette lighter. I can't seem to find much information online if this will work. I don't really want to hardwire it. Any help would be appreciated.


  • +4

    The problem you get with running such long cables that are so thin inside is that you can get some pretty bad voltage drop. This may affect how the camera operates, as USB cables are not designed to carry large loads over long distances.

    What you may be better off doing is running a much thicker power cable to the rear and installing a lighter/power socket in the back. You have to run a cable anyway, so a power cable and a shorter USB cable may be a better combination.

    • +1

      THis is the way to go.
      Not sure how your auto-elec skills are, but I would suggest the following;

      Use one of these to add a fused power source, run a 4mm wire all the way to the back (hide under carpet/ door trims) and attach to a outlet in the back

      The black wire is simply screwed to metal somewhere in the back where it can get a good earth.

    • +2

      Voltage drop is a function of current and resistance, so this isn't necessarily accurate. It's true that resistance is increased over a longer cable, but this only becomes relevant when there's a decent current draw, which a dashcam isn't going to require.

      There's no device that's going to draw enough power over a lead that's even 5m long that'll result in a significant voltage drop even on some of the crappiest of cable (at least enough to render a device inoperative.)

      If you're concerned, get one of these - they're brilliant:

      Better still, extend the 12V socket, not the USB lead.

      • Some of these dash cams require 2+ amp chargers to run them. While I don’t have the facts and figures to the unit OP is going to use, trying to pull 2amps or more through a tiny USB cable over approximately 4~5m of cable run would most likely cause some amount of voltage drop off. OP has to run a cable, so why not run a proper power cable?

        A 2400mA draw over a 5m USB cable could cause a voltage drop of between 1 and 2 volts. at 1000mA, it could be be between 0.5 and 1v. (depending on the quality of the cable. See here for a comparison.)

        Better still, extend the 12V socket, not the USB lead.

        Which is exactly what I suggested.

        • 2amps

          2A is a lot for a device like a dash cam. We've tested the a118, a119s and a119s attached to a GPS module. The two former draws ~500mA while the GPS is ~300mA. We run two a119s + GPS on factory supplied USB cables for both the front and rear.

  • +1

    Best if you have a separate 12V socket in the back, but if not, you can probably tap into one back there.

  • I got my front one done by my trusted mechanic at Arncliffe Sydney

  • +5

    Which car?

    It is possible on some cars albeit harder in some. I wouldn't trust anyone other than myself to run the cable to the rear because I've seen so many of my mates' cars where the cable is tucked under the roof cover but obstructing the airbags.

    Get some steel wire to snake the cable through the A pillar under the air bags and into the roof cavity and snake under the B pillar airbags again.

    You do not want to be crippled or dead in a collision because airbags couldn't deploy.

    • +4

      obstructing the airbags

      Thank you, this is a very good point that not a lot of people would consider.

      • Hence the reason that most wiring should be run along the floor and under door sills if powering a rear outlet socket.

        But yes, If doing the front and your car has airbags in the A pillar, make sure the wiring goes under the bag, not over it.

      • The airbag is designed to burst through the trim of the vehicle and if they were to go off

        The trim of the vehicle where there are airbags are also designed to break and allow the airbag through.

        the airbag is still operational in our experience.

        I wouldn't risk my life based on a retailer's experience.

        There are absolutely no wires and cables (apart from purpose made fasteners) over any of my airbags. The manufacturer has only one conceivable reason to manufacture it that way.

        • Fair enough.

          I tucked mine between the A pillar and the front windscreen, then along the side of the dash between the driver door, down under the driver steering wheel/footwell and to the power socket.

          Theoretically the curtain airbag deploys backwards away from the windscreen, over the side window, right? So I figure there shouldn't be any issue…if there was I would think the airbag would deploy with enough force to push the cable aside anyway…there's plenty of extra cable tucked underneath to avoid any catching/meaningful restriction. At worst the airbag might unplug the cable from the cam or somehow pull the dashcam off the mount perhaps?

          • +1

            @John Kimble: The cable will not necessarilly unplug. It depends on where the force is applied, ie when you pull an extension cord, if it is 90 degrees to the socket, it's still a lot of force before the pins bend and the plug comes off.

            Or if there's any catch/pinch points like when you're washing the car and the hose is stuck under the tire. The hose would sooner snap before it feeds out any further.

            Insulated cables have also surprising one off breaking strain. It deteriorates quickly if shock is repetetively applied but a single hard pull may not break it.

            In any of the above scenarios, it may not stop the airbag from deploying but delaying the deployment or reducing it's deployment force has signficant detrimental effect to its function.

  • Check on youtube?

  • if you buy the dashcams that comes with a rear camera, the cable provided would have had sufficient length.

  • what car do you have?

    • Mazda 2 (2009) and Toyota Tarago (2008). Wanting to do both, I actually have 4 cameras in total (bought another 2 from same seller but on eBay).

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