Finding bad grounds...

Discussion in 'Electrical Systems' started by branbell, Dec 10, 2017.

  1. branbell

    branbell Veteran Member

    223
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    Jun 6, 2011
    Myrtle Beach, SC
    Hey everyone!

    So here is the problem...my battery is dying in less than a week. I put it on the charger...charge it back up and it holds for about a week. The battery is new and I've tried a couple different ones to rule that out..the car is not complete and just sits in my garage and I pull it out and run it once a week.

    Now I did have a complete painless wiring kit put in from the front to the rear by a guy and I'm thinking maybe I have some bad grounds that's killing the battery. Any tips on where to start or how to find them quickly??

    Look forward to hearing from you guys and your wealth of knowledge.
     
  2. SRGN

    SRGN Veteran Member

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    139
    Feb 20, 2009
    Central NJ
    The problem is parasitic draw, not necessarily grounds. Put an ammeter inline between the battery and the battery cable with the ignition off, and doors closed, I'd pull the interior light bulbs to make it easier for later in the diagnostic process. Should draw less than 500 mA, or .5 amps. Especially if you don't have the radio back in the car yet. If it is higher than that, unplug things until it gets low. Start with the alternator. If nothing changes, pull the fuses one at a time until the current draw drops to an acceptable amount. Whichever fuse you pull that reduces the draw, is the circuit that has the problem.
     
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  3. Gary S

    Gary S Administrator Lifetime Gold Member

    21,129
    312
    Apr 14, 1999
    Bismarck, North Dakota
    I agree. Bad grounds would not drain the battery. They would have the opposite effect of adding resistance to the circuit and limiting battery drain. Do what SRGN suggested and try to find that drain that is taking the battery down.
     
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  4. branbell

    branbell Veteran Member

    223
    6
    Jun 6, 2011
    Myrtle Beach, SC
    I appreciate that advice and will do this coming week...as you can tell, I'm not an electrician but this seems simple enough.
    I appreciate it.
     
  5. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member

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    Excellent description!!! SRGN nailer it.
    Just make sure you are on DC amps, and the meter MUST close the circuit, not in parallel.


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  6. branbell

    branbell Veteran Member

    223
    6
    Jun 6, 2011
    Myrtle Beach, SC
    Well I just bought a Clamp Meter yesterday and after reading your reply I checked the description of the item I bought and it says this...
    • Jaw opening measures AC current in a conductor up to 26mm without interrupting the circuit
    That's going to be an issue, right?

    This is the one i purchased... https://www.amazon.com/gp/product/B00NWGZ4XC/ref=ask_ql_qh_dp_hza
     
  7. Gary S

    Gary S Administrator Lifetime Gold Member

    21,129
    312
    Apr 14, 1999
    Bismarck, North Dakota
    I don't believe that will work. It says measures AC current. You need something that measures DC current.
     
  8. branbell

    branbell Veteran Member

    223
    6
    Jun 6, 2011
    Myrtle Beach, SC
  9. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member

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    That should work, it has an internal trigger that sends the power to the ac or dc circuit.
    My 2 cents, don't use the clamp, use the probes, I always get a more accurate read, but my clamp meter is at least 20 years old.


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  10. branbell

    branbell Veteran Member

    223
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    Jun 6, 2011
    Myrtle Beach, SC
    Perfect...just bought it.
     

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