12v car relay timer

Discussion in 'The Projects Forum' started by eg1l, Jun 21, 2009.

  1. eg1l

    Thread Starter New Member

    Jun 21, 2009
    4
    0
    Hello!
    I have a carputer in my car, and when I turn the ignition OFF, it stays on for about a minute, then hibernates. I have measured the current draw after ignition off, and it is draining my car. What I would like to do is to make a 12v delayed relay so the computer has power for 2 minutes after ignition off, and then cuts the main power. I was thinkin a capacitor and some other stuff, but I really don't have a clue. I would believe the relay's coil is about 120 - 150 ohm. Any help with this?

    Edit: When I turn the ignition OFF
     
    Last edited: Jun 22, 2009
  2. Mass

    Member

    Apr 9, 2009
    26
    0
    Tyco has a latching type relay (battery disconnect switch, BDS-A) that you could pulse a signal to after 2 minutes. Then the ignition could pulse the relay to turn it back on.
     
  3. eg1l

    Thread Starter New Member

    Jun 21, 2009
    4
    0
    Guess it is pretty expensive too. I was thinking that I could make something by myself.
     
  4. Externet

    AAC Fanatic!

    Nov 29, 2005
    758
    57
    I suggest you fix what is wrong if there is something wrong instead of inventing circuitry. The carputer does use a few milliamperes to stay alive. You did not mention the amount of current drain.
    Miguel
     
  5. eg1l

    Thread Starter New Member

    Jun 21, 2009
    4
    0
    I came here for help with making a timer relay. The carputer is a closed 2 DIN unit, so I don't want to open it. I still hope somebody could help me with a circuit.
     
  6. Externet

    AAC Fanatic!

    Nov 29, 2005
    758
    57
    Hello eg1l.
    Do you know if it is the engine management carputer or the body management carputer the one draining current ?
    Yes, you can buy one or build a time delay relay. Still do not understand why you want the delay.

    Perhaps something like this:
    http://www.artisancontrols.com/saplugin.htm

    Here is several flavors:
    http://www.odysseytelevision.com/C795240/time-delay-relay--1i.html

    And if you want to do it yourself, many results here :
    http://www.google.com/search?hl=en&q=time+delay+relay+schematic&aq=f&oq=&aqi=g1

    After you implement the removal of power to the carputer, it will forget the driving habits, error codes, and will have to re-learn. Probably not running at its best ever, as may take hours to re-learn. Then, when you shut the car off, there it goes again to start learning. That is why should have a permanent +12V feed to one of the power pins. Like your stereo, to remember presets.

    By the way, after you cut off the power to the carputer and still get drain current, it may be the stereo; or something else.

    Miguel
     
    Last edited: Jun 22, 2009
  7. eg1l

    Thread Starter New Member

    Jun 21, 2009
    4
    0
    Sure thing!

    Hehe, the unit is a audio windows based multimedia player. It has nothing to do with the cars electronics :) A picture may help:

    [​IMG]


    When I turn the ignition off it's supposed to sleep, then hibernate after 18 hours. I have set it up to hibernate at ignition off, but it still draws too much current. It has it's own bios battery etc. so it will not loose settings/memory.
     
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