how can a car battery kill you?

The anecdote you provide above is also an example which aptly demonstrates the theory of "Natural Selection" first proposed by Darwin......

 

There is a big difference between direct current (DC) and alternating current (AC). There are two ways in which electricity can kill.
1) The heating effect of power being dissipated can cook vital tissue.
2) The frequency content of changing current can disrupt heart rhythm.

A battery delivers DC and normally its only effect is heating. Even though DC has no frequency content, when it is applied suddenly the sudden change (in going from zero current to whatever) does contain many frequency components. It is hard to imagine that a car battery applied to the skin could result in sufficient frequency content across the heart to disrupt heart rhythms. Certainly a static electricty discharge (which can be on the order of 40,000 volts) when applied directly across the heart could do so. That is basically what happens when lightning kills someone, although in that instance there is usually some vital tissue being cooked as well.

Most electrocutions are the result of #2 above. Alternating current at 60 cycles per second is close enough to the natural resonance of human flesh that it will cause muscles to contract. When an alternating current like this passes through the heart it disrupts the electrical timing of the heart and can cause the heart to stop beating. Even a tiny altrernating current across the heart can do this.

A defibrillator will fix this if applied soon enough. Also, I have heard of instances of people (especialy linemen) being electrocuted and then reviving when they fell and hit the ground - the impact serving to jolt the heart into a reset so to speak.

 

Even if the incident report exists, I don't believe this story. I doubt that Fluke and other multimeter manufacturers do either, as they continue to sell multimeters with almost needle-sharp probes and no associated warning of electrocution.

 

Actually that voltage drop was due to the resistance of the starter motor winding and the associated cables. The internal resistance of the battery is miniscule compared to the load in that instance.

 

307 deaths per year in the US right there!

 

Good day All,

A couple of comments here:

Firstly, the cooking of tissue is somewhat general. In addition to critical tissue failure, the overall heat can also stop the electrical signals (Action Potentials) in the Nervous System from occurring (the heat denatures the various protein channels that cause the electrical signals to function). In fact I believe that this is one of the causes of death do to high body temps (i.e. fever) and also the "electric chair" used in capital punishment...the brain's neuronal activity permanently stops.

Secondly, DC can also cause problems as high DC voltage can cause an involuntary muscle contraction and so the victim cannot release their grip.

Cheers,

Sam

 

Is the electric-chair A/C or D/C? Let's make electric bleachers and clear out death row..Jacques.

 

It is (high-frequency) A/C.

I'm not going to touch that PC hot-potato with a 10-foot pole....But, I will say that not only do I support abortion --- in some cases, I believe it should be "retro-active"

 

I really find it hard to believe that 9 or 12 volts is sufficient to cause electrocution.
Don't get me wrong, I have a lot of respect for electricity having been shocked by
high voltages inside of tv sets- the anode connection on crt sets carries up to
30kv and b+ voltages on the old sets were around 400v -been knocked to the
floor more than once getting across these while doing measurements.
Always have had the voltmeters around the shop and house (including the simpson 260)
and let my kids play with them and measure their skin resistance.
Think of all the kids and adults around the world that have 9v batteries that
they play around with-the most dangerous thing about them is that the posts
can easily short against something or 2 batteries can be plugged together and
quickly become an incendiary device.
My brother and I use to chase each other around the shop with the old radio
batteries- they were 90 volts!

 

Deaths from 12 volt batteries should occur on a daily basis. How many new car batteries are installed daily, and how many deaths have occurred because a neophyte touched both the -Neg and +Pos posts at the same time. My guess is......well, I think you know what I mean!!

You might get a slight tingling sensation as you would putting a 9V battery on your tongue.

If any of you believe that your car battery can kill you (unless it explodes in your face), stay far far away!!!

Sparky

 

Actually, death is achieved by passing various cycles (differing in voltage and duration) through the body.

 

Somewhere recently I found a neat table that layed out voltages/currents/affects.
This isn't it, but similiar

Electric Current
(1 second contact) Physiological Effect
1 mA Threshold of feeling, tingling sensation.
10-20 mA
"Can't let go!" current - onset of sustained
muscular contraction.
100-300 mA Ventricular fibrillation, fatal if continued



Electric Current
(1 second contact) Physiological Effect Voltage required to produce the current with assumed body resistance: 100,000 ohms ....1,000 ohms

1 mA Threshold of feeling, tingling sensation. 100 V 1 V
5 mA Accepted as maximum harmless current 500 V 5 V
10-20 mA
Beginning of sustained muscular contraction ("Can't let go" current.) 1000 V 10 V
100-300 mA
Ventricular fibrillation, fatal if continued. Respiratory function continues. 10000 V 100 V
6 A Sustained ventricular contraction followed by normal heart rythmn. (defibrillation). Temporary respiratory paralysis and possibly burns. 600000 V 6000 V


Now, as to dying via a car battery - I know of one example.

Saw a 360 in the local mechanic's shop. Dash was completely disassembled. Seems Car wouldn't start, local AAA sent out a guy to jump-start the car. He connected the cables - accidentally crossed them. Needless -to-say the car didn't start. But the lights would flip on & off, the alarm would intermittently go on & off, the trans would shift through the gears. Uh oh.

Yep. Trashed most of the electricals including the ECUs.

Oh, about the death from battery - it was his heart stopping when he saw the repair estimate that AAA caused.

 

, but not unusual!

 

I was told by a physiologist that If you took one lead from a 9V battery, and stuck it up your butt, and attached the other lead to your tongue, it would kill you. Does anyone know where the jumper cable leads in this case had been?

 

I'd be inclined to keep any person who tries this away from small children, pregnant women, and petting zoos.