Getting tired of dead battery. Help?

Discussion in 'GM Electrical Tech' started by 95Chevyk1500, Dec 18, 2009.

  1. 95Chevyk1500

    95Chevyk1500 Rockstar 100 Posts

    This is the fifth time this has happened. This is the first time today it is completely dead. First time it drained was when i left the dome light on and we jumped it and it was fine. This is what I have done recently:
    Replaced fenders (there is a ground on the pas. side fender)
    Replaced bed (ground from gastank and all the tail lights)
    The truck seems to be a clusterf**k of wiring. But theres no lights on when the truck is off, door is shut, the light under the hood is unplugged. I'm really frustrated and really discouraged. Ideas?

    it's 4 degrees, and the truck is garaged.
    Last edited: Dec 18, 2009
  2. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    1st you have to isolate the trouble. Is it the battery, alternator, or some current drain?

    Have the battery load tested, and while your at it, have the alternator tested as well.

    Once you've eliminated those as a source, try disconnecting the battery overnight to see if the battery holds its charge while not connected to anything.

    After that get an amp meter. (caution: the meter must be able to handle a 10amp load) Remove the positive cable and put one lead on the battery terminal and the other on the battery cable. (caution: do this only while the truck is not running) in most cases, the measurement should be less than 1amp. If the measurement is higher you can start pulling fuses to see what is causing the high current draw.

    Let us know what you find. :glasses:

    Just a side note: Once a battery has dropped below 1volt, it is difficult if not impossible for it to recover. You might be able to put a surface charge on it, but for all intents and purposes it is a dead battery. The load test will tell you if the battery is good or not. If you try to charge a "dead" battery it is possible to experience "thermal overload" which is a subject for another forum.
  3. 95Chevyk1500

    95Chevyk1500 Rockstar 100 Posts

    well, i tested the battery. 220 cold cranking amps when its rated for 770. replaced it. it was only 7 months old but it was junk. We'll see. also the truck passed the cnstant draw test, it draws .7 amps when its off, and the test machine said it passed.
  4. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    Did they test the charging voltage? Hope so.
  5. thrasher

    thrasher Rockstar 100 Posts

    If you're handy with a standard volt meter, set it to 20V, start the truck and put the probes on the battery terminals, positive to positive, negative to negative (DUH!!) and have someone bring the rpm's up from idle. It should get to 13.5- 14 volts by about 1700 rpm. If not, then it's not charging.
  6. 95Chevyk1500

    95Chevyk1500 Rockstar 100 Posts

    that test said the alternator is fine to

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