What could cause a new battery to drain down overnight? | Ford Escort Owners Association (FEOA)
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What could cause a new battery to drain down overnight?

Discussion in '3rd Gen 1997-2002 2.0L SOHC' started by redescort99, Apr 4, 2020.

  1. redescort99

    redescort99 FEOA Member

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    Note I am sure I probably caused this last weekend but need to figure out the drain.

    I replaced my battery last weekend. The cables were not marked and needless to say I touched (touched not connected) pos to neg for a split second. As far as I could tell it only blew the radio fuse.

    But something is putting a constant drain on the system as when you are in gear (auto) at idle (very low rpm) the batt light starts to come on. As soon as you raise the rpm, it goes off. Out of gear at idle it doesn't do it or the light is very dim . Overnight the battery goes dead.

    Any idea on where to look? All i can think of is pulling fuses 1 at time and see what happens.
    Probably gone to try the burglar alarm first and go from there..

    Thanks.
  2. Swift

    Swift FEOA Donator

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    It could be the alternator.
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  3. redescort99

    redescort99 FEOA Member

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    Any way to test this? I do have a vom.

    Thanks
  4. FordMan59

    FordMan59 FEOA Member

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    Check the brushes in the alternator to see if they are worn out. When they wore out in my '88 Pony that's the same way the alternator light acted. I replaced the brushes and was still using the original alternator when I quit driving the car at 518K miles.
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  5. redescort99

    redescort99 FEOA Member

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    I think there is something wrong with the alternator, but if so it was me momentarily touching pos to neg. Car only has 87k on it and there was nothing wrong with the charging system until I let the battery go bad over the winter.


    Here is what I have done so far:
    Just to eliminate any variables, I exchanged the new battery for another one this pm.
    Still getting the battery light when not giving it any throttle. With engine running vom shows 17 volts when idle, 18 volts when giving it throttle enough for battery light to go off.

    So something is wrong, but not sure how bad alternator would drain battery overnight. With the other battery after a full charge (and not running the car) it would drain overnight just sitting there.
  6. russix

    russix FEOA Member

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    Please see attached image.

    Attached Files:

  7. pextor

    pextor Moderator Staff Member

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    I believe there is a diode in the alternator and it may be shorted causing your drain.
  8. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    It sounds like you damaged the voltage regulator, and most likely other stuff in the alternator. I'd bring it in to your friendly local auto electric shop for inspection and most likely, rebuild/repair.

    I'm curious how you even touched the terminals the wrong way. I've tried to use a battery with the posts in the wrong orientation so I could use one I had rather than buy a new one, but I couldn't get the cables to reach.

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