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Drain on Battery when car off???

Discussion in 'Electrical Wiring / Questions' started by mattman, Dec 18, 2009.

  1. mattman

    mattman New Member

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    Howdy folks,

    EDIT - SIMPLER QUESTION

    Is it possible a faulty alternator or bad install can place a drain on the battery even when the car is off?

    I have a 1 week old alt (output tested ok), 10 month old batt (tested fine) but there's a 1A drain on the batt when car is off.

    This is in a CURSED WH V6... lol
     
  2. vsl67

    vsl67 Member

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    A mate of mine use to have the same problem it turned out to be the glove box light switch was jammed on so check all of your light switches for a start
     
  3. mattman

    mattman New Member

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    Ah that is a good one :) and hard to see obviously lol.

    Car is back at the auto elec anyway.

    Found out the unit he put in is a Bosch and he said he knows about how the alt can drain the battery, but has never seen a new Bosch unit do it - ever.
     
  4. delcowizzid

    delcowizzid on holiday

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    if its got an emoboliser and stereo theres allways power drain
     
  5. mattman

    mattman New Member

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    Yeah but not so much that it flattens your battery overnight :) I think normal is anywhere up to about 0.2A, this was drawing just over 1A... ie... 5 times more than it should be.

    After a quick charge from RACQ yesterday, it had 2 starts in it today before it needed to be jumpstarted. Fortunately those 2 starts got it to the radiator place then the auto elec...

    Yes, I drive a cursed car :p
     
  6. mattman

    mattman New Member

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    Ok - here's one for you guys... car is all fixed now, $176 later (which I am happy with to have a car that should just work now).

    The issue?

    Well, the BCM drives a relay that drives the interior lighting, BCM had a fault where it wasn't cutting power to the relay when the car was shut off - even though no lights were on, the relay itself was causing enough of a drain to kill the battery. Sparky ripped out the relay and did a "magic wiring mod" so everything works 100% as intended, just no relay and no power drain. Said there's no need to replace BCM unless I want to be really anal about having everything as original (which for the sake of $500 I'm not).

    Drain on battery gone from 1A to 20mA.... I'm happy :)
     
  7. mrvdv

    mrvdv vanders

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    good to see that you got it worked out
     

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