Dead battery, or unknown drain?

Discussion in 'Electrical Systems' started by cgibsong002, Dec 31, 2014.

  1. qn60e6

    qn60e6 Veteran Member

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    Old trick is to pull the negative battery terminal, connect a test light to the terminal and the battery cable, if it lights up you have a short somewhere in the system. That way you will know for sure that you have a short or the battery is bad.
     
  2. wnmech

    wnmech Veteran Member

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    To go one step further with the old trick is once you have established you have a battery drain disconnect one fuse at a time until the light extinguishes.
     
  3. cgibsong002

    cgibsong002 Veteran Member

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    I guess I was just assuming, since it was a nearly 10 year old walmart battery. Issue is, I'm 2000 miles from the car. I was just home getting it ready to ship out to me, and now this issue has come about. My dad is the one messing with it and trying to make sure it's good to ship, but I can't have him try to start trouble-shooting circuits. So I'm a bit uncertain of what to do, but I'm hoping if he can just get it on the truck with a full charge and cut the disconnect, it should be fine until it gets here and then I can start messing with it.

    So, I don't have a test light, but I do have a DMM. I guess the best way is as stated above and just check my current draw? Am I better off pulling a fuse at a time until I see it drop, or pull all fuses and check one circuit at a time? With a non CPU system, should my current be nearly zero? Does anything draw power besides my radio?
     
  4. wnmech

    wnmech Veteran Member

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    When I had this problem on my 77 corvette I pulled one fuse at a time. You will be pulling some amperage if you have the factory in dash clock and of course your dome lights will have to be taken out of the picture. If you got 10 years out of a Walmart battery that might be the first thing I would replace. You might first have the old battery load tested.
     
  5. cgibsong002

    cgibsong002 Veteran Member

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    Thinking about it more.. some issues that come to mind. The seat belt buzzer would always go off randomly when the car was off and sitting in the garage. I disconnected the actual seat belt connection, but I guess it also is connected up with the door switch, and maybe headlights? I never did figure out why it would randomly go off. Couldn't see that causing too much drain, but maybe something.

    Dome light connection was never sturdy. Have had to tap it a few times in the past to get it to turn on. Can't see that causing drain though if the doors are closed. Maybe related to above?

    My ground connection for my amp is poor, I know this for a fact. But this is tapped into my heater circuit, so it should be getting no power without ignition, so I can't see this being anything relevant.
     
  6. hessdawg

    hessdawg Veteran Member

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    Your amp is connected to the heater circuit ??
     
  7. cgibsong002

    cgibsong002 Veteran Member

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    or the ac.. I forget which. but i have both of those disconnected.
     
  8. cgibsong002

    cgibsong002 Veteran Member

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    Well, a little long overdue, but I finally got my DMM and did some testing today. Believe it or not I was only pulling 5.8mA unlike what we all expected.

    However, I did notice a loose connection on my dome light, and a bad ground on my amp, both of which I fixed. I'm not sure if one of these might've intermittently been the cause, but unfortunately I don't know for sure since I couldn't produce any more than a 6mA draw. The battery also seems like it has no problem providing plenty of juice to crank the starter.

    So I guess at this point all I can do is wait. Maybe the light or amp was the issue and it's fixed now, or maybe something is still wrong. If I go out one day and the battery is dead, hopefully I can get the meter back on and find something. We'll see.
     
  9. camaro6662

    camaro6662 Veteran Member Lifetime Gold Member

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    also clean the battery it can also draw down a battery over time.also check the cells in the battery
     
  10. Itsadryheat79

    Itsadryheat79 Veteran Member Lifetime Gold Member

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    -- I enjoy watching Eric the Car Guy .... :)
     

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