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OT: Story about a guy killed demonstrating to kids how safe a 12v car battery is?

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  • #16
    I agree with Ohio Mike. Everyday work around car batteries, it seems the risk of explosion would more of a real danger than some 12 volt poke. More of a burn possible if you managed to hold onto a shorted tool or wire. (As a kid I did manage to spot weld a car door to the other car's fender I was jumping using wrong polarity).

    Heck I guess a cup of hot coffee might kill ya' if you "do it just right"..
    S E Michigan

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    • #17
      I used to have a bad habit around car batteries --- working on mostly smaller vehicles I was always looking for "shelf space" and although fully aware of what "could" happen did it anyways, yup - used the top of the battery with mostly stuff that would not matter and very quick like strategically placed it so it was really not a threat,,, but then one day I built up quite a collection --- still keeping the area around the positive terminal clear by good margin ---

      but you know how it goes --- heat of the battle stuck bolt or whatever and I moved stuff around to where about 4 different tools made the connection and had a major arc that took out a fair chunk of battery terminal and a little of the open end of my 13 mil wrench lol

      still was not a total wake up call, but was more careful --- then one day im wrenching away and see that i had a can of brake clean on top of the battery, and even though nothing instantly threatening around it - it shook me up WAY more then the wrenches,,, something like that might kill you or at the very least totally disfigure you ----- I do not use batteries as shelves anymore at all... im done with that type of high risk behavior and im glad...

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      • #18
        So you guys don't think if you grabbed a battery lug in each dripping wet hand something spectacular could happen?
        Location: Jersey City NJ USA

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        • #19
          I thought it was like the safety course work sent me on where the guy taking the course stated, “7 people were killed by 9v battery’s in the U.K. last year”, I laughed, he said I’m serious, I laughed some more, apparently they met their tragic, somewhat Darwinian end falling off ladders changing the smoke alarm battery, I mean killed by a 9v, more like killed by gravity but that’s how these safety nutters work, bear in mind this was an electrical safety course!
          mark

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          • #20
            Originally posted by boslab View Post
            I thought it was like the safety course work sent me on where the guy taking the course stated, “7 people were killed by 9v battery’s in the U.K. last year”, I laughed, he said I’m serious, I laughed some more, apparently they met their tragic, somewhat Darwinian end falling off ladders changing the smoke alarm battery, I mean killed by a 9v, more like killed by gravity but that’s how these safety nutters work, bear in mind this was an electrical safety course!
            mark
            LOL! that's like saying a guy was killed by his dog if he has a coronary dragging the kibble bag. That said, f**k ladders!
            Location: Jersey City NJ USA

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            • #21
              Volts? Amps? Power? What actually kills?

              When answering this question you must remember the most used law in electricity: Ohm's Law.

              I = E / R

              There are three things represented in that law/equation: Volts, Amps, and Resistance. And they are very tightly inter-related to each other. If you know any two, you can always find the third.

              And then there is power: P = IE

              But combining those two equations we can see that power can be found if you know any two of the same three things:

              P = I^2 R

              and

              P = E^2 / R

              There is no way to separate those three things. They are totally inter-related. So trying to say that anything is due to just one of them is NEVER accurate.

              Low Voltage with low resistance can mean a high current. But a high Voltage does not necessarily mean a high current because the resistance can also be high. You must consider all of the circumstances. In this case, with Ohm's law in effect, you must know and consider two of those factors: then the third one will be determined.

              And there is more than one way that an electrical shock can harm or kill someone. Yes, an electrical current can stop the heart. But it can also generate heat which can kill. How about paralyzing the lung and stopping breathing? I would not be surprised if there were other mechanisms. And some of these mechanisms may rely on a certain Voltage while others may work due to a current level or even to the amount of power dissipated inside the body.

              So, can a 12 V battery kill? I would not be at all surprised if you can get the resistance low enough (wet and salty hands) and have the current flow through the heart or another vital organ (in one hand and out the other). Why else would the manufacturers of automotive jumper cables bother to INSULATE the clamps. On the other hand, I have been personally bit by 40,000 Volts. It went in my left hand and out of my left foot: I found burn marks in both of those places. And it passed through not one,but two insulators on it's way. I felt the effects for several hours but it did not kill me or even require any treatment. 12 V kill and 40,000 V no harm, both with the heart in the path of current flow? The difference is resistance.

              PS: I strongly recommend that automotive jumpers be connected and disconnected ONE clamp at a time. And the last one to be connected should always be the negative one to the body of the vehicle with the good battery. That one should also be the first one to disconnect.

              As for 40,000 Volts, just stay away from it. I most certainly do; once was more than enough.
              Paul A.
              SE Texas

              And if you look REAL close at an analog signal,
              You will find that it has discrete steps.

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              • #22
                Back in the 1960's, I was a checkout technician, working on large control panels that were all 120 volt relays and step switches. "Large" as in maybe 12 feet long or more that you walked into. The relays were telephone type, with sockets wired with taper pins, using #20 or #22 gauge wire. While troubleshooting, it was pretty easy to touch a pin and get a jolt. My boss told me "if you don't get bit at least once per day, you aren't working hard enough". He was actually right.

                I've gotten a lot less comfortable about such things in later years. :-)

                Not sure of the rules, but it seems as though 48 volts and below is considered "safe", and above 50 volts, not so much.

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                • #23
                  There is a phenomenon called Electric Shock Drowning (ESD) which has seriously injured and even killed people who were swimming near a boat which was leaking electricity into the water. Interestingly, it usually occurs in fresh water, and not salt water.

                  https://www.huffpost.com/entry/esd-h...-fres_b_693454

                  A study of "let go" currents and voltage:

                  http://www.wright.edu/~guy.vandegrif...%20Dalziel.pdf

                  12 VDC pool lighting has caused some injuries and death:

                  https://www.poolspanews.com/how-to/c...imming-pools_o

                  Other discussion:

                  https://electronics.stackexchange.co...a-shock-or-not

                  I have heard of a "party trick" where a coin is placed on the bottom of an aquarium filled with salt water, and a 12V battery supplies current through a couple of electrodes. The "victims" are told they can keep the coin if they can pluck it out of the tank. But the current paralyzes the hand and it cannot be done. I have not tried it, so... CHALLENGE!
                  http://pauleschoen.com/pix/PM08_P76_P54.png
                  Paul , P S Technology, Inc. and MrTibbs
                  USA Maryland 21030

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                  • #24
                    Originally posted by PStechPaul View Post

                    I have heard of a "party trick" where a coin is placed on the bottom of an aquarium filled with salt water, and a 12V battery supplies current through a couple of electrodes. The "victims" are told they can keep the coin if they can pluck it out of the tank. But the current paralyzes the hand and it cannot be done. I have not tried it, so... CHALLENGE!
                    That coin better be silver or better!
                    Location: Jersey City NJ USA

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                    • #25
                      I knew a top notch foreign car mechanic who had survived the Chosin Reservoir and a Chinese charge without getting wounded. He had these really nice fender blankets where tools were kept handy without damaging the paint. One day something caught when he moved and dragged the blanket a little. A wrench tumbled into the battery area and he lunged after it. It apparently shorted the terminals and the battery exploded. The plastic between the terminals came up and removed an eye and most of an orbit bone from his head. It was touch and go for a few days but he survived and was back at work about 8 months later wrenching with only one eye.

                      I had an alarm on my Harley that had little balls in it that moved and broke a circuit if the bike was tampered with. I was riding one day with a pal and the bike just shut off. Aside from the alarm I only had about 15 wires that I did myself so I knew it well.
                      I was in a busy New Jersey highway gas station side lot and leaned in to take a look at things.
                      The little Yuasa 7 amp hour battery made a loud pop, split wide open and sprayed acid all over me. Fortunately I was wearing my glasses., The instantly alert gas station attendant immediately grabbed the windshield wash pail and ran as fast as he could to dump it over my head. He then took my hand and led me to a fresh water hose where I could rinse off. I gave him a $20.
                      I got my van, took the bike home and found the alarm module had completely melted. I ditched the battery and alarm circuits put in a capacitor thingy and reinstalled the magneto I had recently removed because it was getting too tough to kick over with 11/1 pistons. That’s kinda why I have a metal right knee.
                      Illigitimi non Carborundum 😎
                      9X49 Birmingham Mill, Reid Model 2C Grinder, 13x40 ENCO GH Lathe, 6X18 Craftsman lathe, Sherline CNC mill, Eastwood TIG200 AC/DC and lots of stuff from 30+ years in the trade and 15.5 in refinery unit operations. Now retired. El Paso, TX

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                      • #26
                        Originally posted by gellfex View Post
                        So you guys don't think if you grabbed a battery lug in each dripping wet hand something spectacular could happen?
                        Just tried it --- - nope nothing spectacular, in fact not even a tingle...

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                        • #27
                          Originally posted by Mike Amick View Post
                          I always cried foul when Rambo was tied to a chair and the bad guys had the jumper cables and was making sparks with them and everybody's eyes got
                          big out of fear. But the movie industry does have a lot of people believing this.
                          That's funnier than crap --- ohh im scared lol

                          Geeze - show Lorena Bobbitt with a knife if you want to get some attention --- hell id probably run out of the theater kicking and screaming...

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                          • #28
                            Originally posted by gellfex View Post
                            So you guys don't think if you grabbed a battery lug in each dripping wet hand something spectacular could happen?
                            In 999 case of 1000, nothing at 12V car battery. Some particular cases, of the right (wrong?) person and the exact set of circumstances, something could happen. At 12V, not very likely, but possible.

                            At 24V, yeah, more chance of that strange combo of things that makes a problem. 36V, or higher, nah, not a great idea to do it. Every voltage increment makes a problem more likely.

                            The Ohms law argument seems like a perfect one, and yes, it always applies. The problem is that some of the variables may not be known, or may change. The "resistance of a person" is not a specific number. Usually, I find I am around 10k ohms if trying to make contact. But, in the first place, a lot of that is skin resistance, dry skin, and so that varies,

                            It can vary a LOT. If you have basically dry skin, and you dip your hand in water just before the measurement, probably it will be lower, but there is still a layer of dry dead skin all over you, with water on top of it.

                            If you have just been swimming for some time, that dead skin layer is probably not dry any more. Same if you are in a humid environment, and have been sweating for some time. Your resistance is going to be a lot lower. You are a bag of salt water, and if the electrodes are directly in the salt water, that is going to be lower resistance. That dead skin layer is a bit like wire insulation. If you soak that layer so it is pretty saturated with conductive impure water, all bets are off.

                            If you have literally thin skin, the dead skin layer is thinner, and all the effects are multiplied. And, in some cases, I understand that conducting a smaller current can make the skin resistance drop, which will lead to a larger current.

                            So, have fun with ohm's law, but you will need the right resistance value to plug into it.
                            CNC machines only go through the motions

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                            • #29
                              Never had a battery explode, but a friend had an interesting experience one day. He was welding something under the hood and was hearing the occasional pop. Turns out that sparks were reaching the battery, and the caps were popping off. Said he felt pretty lucky the battery didn't explode.
                              I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                              • #30
                                I read about exploding batteries, apparently hydrogen explosion, really fast brutal thing, I’ve held batteries in reverence ever since, I have a sheet of rubber switch room mat to put over when working but prefer removal though with new cars you need a 12v battery saver or setting saver as the bloody car gets amnesia if it looses power, everything gets lost even the ignition keys, how dull it that, keyless start my arse, I found out when I lost my radio, it asked for the code, second hand cars don’t come with codes, main dealer stung me for £60 to “decode” my own radio
                                biggest hydrogen explosion I saw the result of was a 5m x 6m hole in the shell of a blast furnace, 2” steel with 3’ of refractory behind it blew the lot 400 feet, the investigators said it was lucky it was a small explosion, it lifted 40k tons 6” and rotated the furnace 18”, pipes and all, I suddenly developed severe paranoia when lugging red/orange cylinders into the gas cage at the lab, I did not like hydrogen cylinders (apart from the back as wards fittings)
                                I can easily see how a battery can end you if it blows in your face, although these lithium things can go bang too
                                mark

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