Help Please! Electrical Shock From Battery!


#1

Today I was shocked from a deep cycle marine battery (12volt I think?) full on and it really jolted me. Shot straight up my arms to my armpits and chest where I really felt it! Has anyone ever been shocked like this? Are there known health risks that I should be aware of?

Thanks for your help


#2

I have accidentally created short-to-ground situations several times and have been shocked as you describe once. I was leaning against the body of a truck I was working on and touched the metal band of the watch I was wearing against the positive battery terminal. It did not feel good, but I would not describe it as graphically as you did (although you are describing something that happened recently, while my experience was several years ago and perceptions change over time). The only ill effect I had was some very minor burns where my watch band sat on my wrist, just a slight red outline, and I did feel the current go through my body. My guess would be that if you feel okay now, you will be fine, but I am no doctor and if you are concerned about it I suggest you see one or at least call your local hospital and speak to an on-call nurse. If nothing more, it will give you peace of mind. I did nothing about my experience other than learn to be more careful in the future. The reason I did nothing is because as soon as I let go of the car it stopped hurting. If you are still feeling it, you should see a doctor. For me, even the jolt of 40,000 volts from an ignition coil leaves no consequences lasting more than a few minutes.


#3

Once backed into a pair of exposed household wires in a ceiling fixture and took 120VAC to the top of the head for a fraction of a second. After I stopped vibrating I carefully got down off the stepladder and went to lie down for a few minutes.


#4

I have never experienced an electric shock from 12V though I suppose it is possible if there is enough contact area and you have wet skin.
Was a battery charger hooked up at the time? A certain kind of ground fault can leave the chassis of the battery charger hot, the same voltage as the hot wire of the 115 volt circuit that powers the battery charger, but it will still work normally, the charger and battery being like a bird on a powerline.
I have been bitten by 115, 230, 460 volt ac mostly by accidently brushing against it. I don’t work on 2300/4160 volt 3 phase too often but when I do, it’s with extreme caution.


#5
 That does not seem right.  12V should not cause you a problem and that battery should not be over 14.5V or maybe 16V when being charged. 

 If the engine was running, then I would have to guess you are getting a high voltage from a plug wire or some other part in the spark plug chain.

#6

If the conditions are right, 12-14 VDC can indeed give you a good jolt…Electrical shocks do indeed pose a health risk. The solution is to avoid them. Never present yourself to both the positive and negative posts of a battery at the same time, especially with wet hands! Blood is very conductive and so is wet, salty skin…


#7

It may be the current rather than the voltage. Static electricity sparks are in the tens of thousands of volts. Take a little rectangular 9 volt battery such as you might find in a radio and touch the two terminals to your tongue. Good fun. Try the same thing with a 9 volt battery the size of a car battery.

Here’s an experiment you can easily try at home: get 8 dry cells, 1.5 volts each. Connect them in series with tape, then touch one finger to each terminal. Does it feel the same as when you touched the car battery?


#8

12 volts is 12 volts…But a car battery can provide 300 amps of current while 8 “D” cells can not…The key factor here, the missing link, is the RESISTANCE in the circuit…Your body can present a VARIABLE resistance depending on many factors…

Take your ohm meter, set it on 100 ohms and hold the probes one between the fingers of each hand…Now wet your fingers with a little salt water and try it again…If you can get yourself down to less than 10 ohms, 12 volts can become dangerous…


#9

I appreciate the clarification that 12 volts is 12 volts (very Ayn Rand), and the fact that you backed me up on the current issue. For those who enjoy doing the lab portion of the lesson, the batteries don’t have to be D cells.

There are parts of the body you do not want hooked up to a car battery, but if it’s come to that you might as well tell them what they want to know.


#10

I think there has to be something else going on here. 12 volts does not penetrate the skin, even if it is wet. It can send current over the surface of wet skin, but it does not penetrate.

A deep cycle battery has less available current than a normal car battery. It is designed to provide less current, but for a much longer period of time. Something else is going on here. If the OP was on a dock and reached into a boat that had been traveling through water, then he(she) could have gotten a bad static shock, but thats due to a build up of static electricity from plowing through the water, not from the battery itself.

One more little detail, the battery is DC. DC is inherently safer than AC. A little demonstration that the Edison group used to do back during the “Current Wars” was to shock a dog with 500 VDC. It would startle it for a few seconds, sometimes cause a small burn, but it didn’t do any lasting damage. The they would hit the dog with 110 VAC and the dog would die. This was done to scare people away from AC and go to DC. In fact the electric chair was invented by the Edison group to use AC to execute convicted criminals to show the public how dangerous AC was to have in their homes.

The frequency of AC electricity, 60 hertz, is very close to the frequency of the nerve impulses to control our heart. That is why it so often disrupts the nerve impulses, leading to fibrillation, which is an irregular heartbeat that does not push blood through our bodies.

DC burns. I was working on a power supply once when I accidently sent 500 VDC through my body. I never felt a shock, but when my hand started to burn where it was grounded, I felt that.


#11

Everything Keith said is correct, but if the engine was running at the time the alternator or the distributor can give you one hell of a jolt, especially if things are wet. If the OP brushed his hand up against a dizzy with a cracked cap, he could easily have gotten an impressive shock.

The good news is that if it didn’t kill him, and didn’t burn him, it’s not going to cause any long-term damage either.


#12

Try grabbing a spark plug wire sometime if you want a heart starter. If your heart didn’t stop, and you have no burns, you should be fine. I kind of think there might be something else going on though that you should check into. There have been stray voltages through the actual ground that under the right conditions can cause a problem.


#13

“A dizzy”? Is that the thing on top of the ginny with wires going to the sparkies? Let’s nip this in the bud, shall we?

“Tranny” is bad enough. I don’t think I have to explain why.


#14

What was that, the US and British divided by a common language?


#15

It’s hard to believe you got a shock from a 12-volt battery. It normally takes at least 35 volts to overcome the resistance of even wet skin. When working on my car, and someone mentions being afraid of getting shocked by a car battery, I’ve licked my fingers and touched both battery terminals as a demonstration–no shock, harmless.

But if you touched the terminals with damaged skin, or managed to get one arm across both terminals, that might be a different story.


#16

Voltage is irrelevant. Amperage is what you feel, and a fully charged battery can push some decent amps.

I remember a show I went to a long time ago, where a guy stood on top of a black cylindrical container type of thing, and shot “lightning” off his hands. It was pretty impressive way back then, when I was a kid. he went to great lengths to explain voltage (he was using several thousand) and amperage (he was using less than .1). That combination made it safe (enough) for him to stand on. He even had an audience member (someone I knew, so not a plant) do the same thing. I think he was the only one in the audience without any metal in his clothing that he couldn’t remove.


#17

Voltage is relevant. A battery cannot “push some decent amps” just because it has a high capacity. It takes either a high voltage or very low resistance to “push some decent amps”. Simple Ohms law.


#18

Chassios, you can think of voltage like pressure and amperage like flow. It still takes enough pressure to overcome skin resistance to initiate flow, then it’s the flow that’s the killer. 12 volts isn’t enough for this.

In the demonstration you saw, a Tesla coil was likely being used. This brings another variable into the equation—frequency. Tesla coils use a very high voltage at a high frequency. This causes the current to behave in accordance with the ‘skin effect’, comparable to energy in a radio antenna, where the current is carried mostly by the outside layer of the conducting material. “Lightning Man” was able to get away with not being injured by a combination of low current and the skin effect which kept the deadly current from going through his heart and other internal organs. I’ve played with Tesla coils myself, and shocking as this may be (bad pun, I know), the only real hazard is if you keep the arc going long enough, it can give you a bad burn.


#19

Tesla coils have an air core which limits current flow.


#20

I worked 31 years in an electronic factory. Yes, 12 volts can hurt. It is the current through your body that hurts. In fact, under optimum conditions, as low as 20 milliamps can kill you. That approximate figure is standard in all safety manuals.

Clean, dry skin has high resistance. Under a metal watch band or a ring can be VERY LOW resistance. Electronic techs are very curious people, and some years ago, we actually did some skin resistance measurements after a safety talk. After this many years, I obviously can’t clearly remember, but we had some measurements that were in single digit ohms on men who wore wedding rings all the time.

If you have a wedding ring, slip it up a bit and see the difference in the skin there and on other fingers. If the ring hits the voltage, that ring has very wide contact with the low resistance part of the finger.

Look up parallel resistances, and you will see a ring is like having many, almost infinite, parallel contacts with your finger, instead of only one where you touch that 12 volts terminal at one point. Ditto with a metal watch band.

That is why I have not worn a wedding ring since around 1968. It’s not worth the risk, and even when I retired, I will never wear one, perhaps from lifetime habit.