Car head Unit Accessory wire

Discussion in 'Prius c Audio and Electronics' started by Hartish Khoobarry, Nov 30, 2018.

  1. Hartish Khoobarry

    Hartish Khoobarry New Member

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    Hi Guys,

    How many devices can I connect to the car head unit accessory wire?

    Currently i have the car head unit , a dash camera and a rear camera connected to the car head unit accessory wire. I am planning to add foot well lights and also connect a digital Processing System (DSP) to car head uni accessory wire?

    Is possible to connect all these device to this wire?
     
  2. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    There is no arbitrary limit to number of devices, just the total amount of power available.

    Check the fuse supplying that line.

    Then add up the power demand of each of the devices you plan to add. As long as the sum of demand is less than the limit allowed by the fuse, you're fine.
     
  3. Hartish Khoobarry

    Hartish Khoobarry New Member

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    How can I calculate the demand power?..Can you provide an example?
     
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    You'll have to research each of your devices. It'll be in the specs or instructions for each. Stereo may take 5 amps... maybe the processor takes 1, dashcam 1.5 etc... so add that all up. Then find the fuse feeding this branch circuit (owners manual ought to have this info) and make certain that your aggregate demand (7.5 amps in my example so far) is lower than the fuse rating. It is probably a 10 or 15 amp fuse (just guessing) so in this example you would be fine.

    If you can't find the info, you can take direct measurements with an ammeter.

    If your total demand is higher than the rating, you will have to power some of these devices from a different branch circuit. Never replace a low-rated fuse with a higher-rated fuse, that's a serious fire risk.
     
  5. Hartish Khoobarry

    Hartish Khoobarry New Member

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    I have done some research and here is my results:-

    Prius C HeadUnit/Dome Light Fuse rating = 15 A

    Currently i have install these devices which works well and haven't got any problem so far:-

    Kenwood DDX917-WS (Head Unit) Maximum power consumption = 15 A
    Kenwood DRV- N520 (Dash Camera) Maximum power consumption = 0.4 A
    Kenwood CMOS-320 (Rear Camera) Maximum Power Consumption = 0.1 A

    In the future, I am planning to install there 2 devices:-

    Led footwell power consumption rated at 2 A
    Alphine DSP PHX800 rated at 10A

    What do you advise?
     
  6. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I would find another circuit to host the Alpine & lighting.

    You are already slightly over the limit, but the head unit consumption is extremely variable, and will only have brief peaks at full rating. This is why the fuse hasn't blown already, despite that unit having a high demand listing. I don't think you need to take anything off that circuit, but I wouldn't add any more.

    Find another switched accessory circuit, or create a new one with a new fuse feeding a new wire run from the underhood electric panel.
     
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