Jumping a Car Battery

Discussion in 'The Garage' started by Shockmaster, Apr 28, 2018.

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  1. Shockmaster

    Shockmaster Registered User

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    Not too long ago I had to help a neighbor jump-start her car. I pulled my car up next to her's and connected the cables to each positive and negative terminal of each battery as I usually do. My neighbor started to panic as she read on the internet that connecting to the negative terminal on a dead battery could cause a spark, which in turn would ignite hydrogen from the dead battery and cause an explosion. I told her I've jumped batteries this way before and nothing bad ever happened, but she wouldn't have it. So I had to search for the metal ground connection in her car's engine (which was put in the most ****ing stupid place by the manufacturers). I eventually found it and got her car started for her.

    Later on I searched the internet myself and found a lot of material backing what she said about not connecting the cable to the negative terminal of the dead battery. However, whenever I ask people who work in repair shops or people I know that are good with cars, they say there is nothing wrong with connecting the cable to the negative terminal of the dead battery.

    I'm curious on what other people think. Is it really unsafe to connect the jumper cable to the negative terminal of the dead battery? Or is that basically an old wives tale?
     
  2. Winger98

    Winger98 powers combined

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    I'm with you, I always just hooked each cable up to the its corresponding terminal and jumped away. I've heard it's dangerous, and I'm sure someone will put up a youtube within five minutes of my posting this, but I've never actually seen anything bad come of it. For me it's like cell phones at gas stations.
     
  3. Nullus Reverentia

    Nullus Reverentia Hic Sunt Dracones

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    Every mechanic I've heard whose talked about this say it's a load of ****. Urban myth it sounds like.
     
  4. GarbageGoal

    GarbageGoal Heel, you say? Sponsor

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    Even most jumper cable instructions say connect it to a bolt on the engine block or some other grounded metal part.

    I think for the most part it's fine, but if something is messed up in your electrical system you don't know about (yet) it's the easiest way to cause an issue.
     
  5. ProstheticConscience

    ProstheticConscience Happy Chappy

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    Urban myth. The negative terminal on the battery is just a ground that completes the circuit anyway.

    I've had to jump-start a lot of vehicles. Used to work in RV rental. Done it probably hundreds of times. Never had any issues with connecting jumper cables to negative terminals.

    The real danger is mixing them up and reversing polarity. Then the sparks fly.
     
  6. Chonged

    Chonged Registered User

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    Just Have to Make Sure Once the Car Is Started to take the Cables Off Immediately

    the Blow Up thing Is When You are Double Charging a Battery
     
  7. New Jersey

    New Jersey least useless

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    I have a 2013 Impreza still under Subaru warranty and a jump starter battery pack.

    One time I left a map light on all night and the battery went flat.

    Positive on first, off last. Nothing bad happened.
     
  8. Roboturner913

    Roboturner913 Likely never played

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    Attaching to the negative terminal can cause a spark. I've seen it happen. Is it super dangerous? I doubt it. I guess if you had a pretty big buildup of hydrogen gas, but you'd have to charge the battery for hours and hours for it to create enough gas for a spark to ignite.

    But I mean, it's usually super easy to find an unpainted metal surface to ground to. I usually use the hood latch.
     
  9. Plural

    Plural Registered User

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    It can cause a spark. It won't explode. Car batteries are grounded from one terminal anyways.
     
  10. Plural

    Plural Registered User

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    Yeah, the negative terminal is grounded. Mixing the cables is dangerous.
     

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