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2G Battery drain overnight

Posted by DsmMickey, Dec 17, 2015

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  1. tametalon92

    tametalon92 Supporting VIP

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    I agree with most of what you said, especially checking running and not. One should also check with it above idle rpm.

    However, if you have a battery reading 12.2v (that's 40% charge) from sitting overnight alone, you probably have a draw. Unless you make 20+ 5 mile trips in a day, you should never have a battery below 12.5v.

    I just bought a brand new adv. Gold agm from sears, got home and tested it, 12.3v. Put a 15 amp charge on it, boom, 15.5v. would draw down to 10.1v with a 200a load after about 10 sec, batt was sulfated. Took it back and exchanged it, and this was a batt manufactured in November.

    I don't put up with mediocre readings from electrical systems. If there's low or bad readings, I found out why and where.
    Identify, isolate and eliminate, haha
     

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  2. 91Bomb

    91Bomb Proven Member

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    If brand new battery is 12.5-12.7v, how is 12.2v 40% less?

    if I see 12.0v on my older battery after not starting car in a few days but it cranks right over + starts I'm not too worried.
     
    Last edited: Jan 29, 2016
  3. tametalon92

    tametalon92 Supporting VIP

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    Because 6v is not 50% life. There are 6 cells in a battery, each at 2.1v. When you take out total voltage to 12.2v, you lose a massive potential to "push" current.

    And I apologize, 12.2v is actually closer to 60%

    Here is a good reference that is close to accurate
     

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  4. 98eclipse2015

    98eclipse2015 Proven Member

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    the battery is new and so are the terminals it turned out to be a bad alternator took my car in to get my new alternator tested along with my old one and yup turned out it was a bad one.
     
  5. JPringels

    JPringels Probationary Member

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    Rockford, Illinois
    currently having the same issue with my 96 TSi, replaced battery, terminals and ground wires and ring terminals, i get dashlights, key dinger and courtesy lights but no crank. jumped it with the charger and it started just fine, ran back into the car and now my battery light is on (wasnt before, with the same issue) think im going to dive into taking the alternator off after work and have it tested. i pulled the battery out of it and put it in my daily and started right up no fuss this morning. so i know the problem is not the battery but something drawing amps on it,
     
  6. luv2rallye

    luv2rallye DSM Wiseman

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    Minneapolis, Minnesota
    If it won't crank but you have power to other things then you either have a weak battery or poor connections in the large battery cables (high resistance drops too much voltage so not enough voltage at starter terminals). May even be the cable itself.
     

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  7. 98eclipse2015

    98eclipse2015 Proven Member

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    tigard, Oregon
    i had a battery drain that was killing my battery i fixed that for the most part. mine ended up being the keyhole light i just took the bulb out LOL
     
  8. JPringels

    JPringels Probationary Member

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    As soon as I get paid Friday and have the time, am gonna dive into it
     
  9. 98eclipse2015

    98eclipse2015 Proven Member

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    it was the battery I have a red top now
     

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