About jumping car - Connection Negative

About jumping car - When attaching NEGATIVE to the target car - what is the difference btwn attaching to battery negative pole and attaching to the metal part of the car ?

Why "attaching to the metal part of the car" is the "default instruction" than otherwise ?

Thanks

Reply to
klabu
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You can get a spark when the last of the four connections is made. Its best if the spark is not close to the battery for safety reasons.

Don

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Reply to
Don

A battery can emit flammable gas. That last connection generally gives you a spark when you make it so they recommend that you use some other piece of metal to keep that spark away from any potential gas. I once saw a battery explode from jump starting. Sent the person hooking up the cables to the hospital. Possibly he hooked the cables up backwards but ever since I have been a bit more careful jump starting cars.

Steve B.

Reply to
Steve B.

When you attach the LAST connection, there will be a spark as the circuit is made.

You want that spark to be as far away from the battery as possible. Batteries can produce explosive gas. You don't want a spark right near a source of explosive gas.

Because, to paraphrase Repo Man, "sometimes batteries just explode."

--scott

Reply to
Scott Dorsey

"klabu" wrote in news: snipped-for-privacy@corp.supernews.com:

Automotive lead-acid batteries DO (not "can") produce and emit hydrogen gas as a normal part of their operation. Sparks ignite hydrogen, a *highly* flammable gas.

As others have pointed out, the last connection you make with your jumper cables usually makes a bit of a spark, so you want that spark to happen as far away from the hydrogen as possible.

Ever heard of the Hindenburg?

Reply to
Tegger

Aww, come on. Only 36% of those aboard the Hindy died. Ford engineers would do backflips with safety numbers like that. OT? Yes. Flame magnet? Oh yeah.

Toyota MDT in MO

Reply to
Comboverfish

Usually when jumping a car you are outside with the wind blowing. If so hook the negative to the battery. No gas will ever get the opportunity to collect under these conditions.

Reply to
tnom

Absolutely false. Since the disaster happened nearly seventy years ago, I would be very surprised if anyone aboard the Hindenburg remains alive. Even the Pinto has better statistics than that.

--scott

Reply to
Scott Dorsey

i agree because i jump my brothers car when it was real cold and battery popped..every since then i ground it to anything but neg cable..theres my 2 cents worth on this suject...

Reply to
Scrapper

It is a safety risk, but I agree...seldom do you have enough hydrogen accumulated to turn the hazard into an accident. But it CAN happen.

We are looking at statistical risk.

A proper risk assessment would point toward using the procedure whereby the ground or B- cable is hooked to the frame.

I have seen cases where hooking both cable terminals to the battery in tight spots might lead to them getting together. In a perfect world, it shouldnt happen, but the risk can be there.

"Risk", as in the Challenger explosion, the Hinderburg, and the Titanic, can sometimes become catastrophic fact.

Reply to
<HLS

snipped-for-privacy@panix.com (Scott Dorsey) wrote in news:eq4mhn$sks$1 @panix2.panix.com:

As HL Mencken once put it, the death rate has remained constant forever: one per customer.

Reply to
Tegger

I was outside at -30 or so with the wind blowing and had the top explode off a battery when I disconnected it! The draw on the vehicle was enough to set a small spark off. The hydrogen gas had collected 'under' the battery caps. The whole top of the battery blew off.

It blew pieces of the battery through the hood and sliced up my face. All my clothes were ruined but luckily there was a snow bank for me to dive my face into with running water steps away inside.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06
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Reply to
Mike Romain

This might also have been a pressure explosion rather than a detonation.

Hydrogen is to be expected inside the battery, but there is seldom the right combination of hydrogen to air composition, spark, etc to make it blow. Otherwise we would see it happen a lot more often.

Doesnt take but once, regardless of the cause, does it, Mike:>)

Reply to
<HLS

Not really, your looking at superstition not statistical risk. Hooking the negative cable up when jumping a battery is not likely to cause an explosion. Why? Because charging a battery is what causes hydrogen and oxygen (in just the right proportions) to build up inside the battery.

The real risk is in creating a spark after the cables have been hooked up and the battery has been charged for a while. Typically when a battery explodes it happens after the receiving battery has been subjected to a very rapid charge and then the cables are adjusted or disconnected causing a spark. Usually its after attempting to crank the engine that someone decides to wiggle the positive lead to get a better connection.

-jim

Reply to
jim

I have seen several blown up batteries over the years. Some blew up when the key was turned to start the car. A sudden discharge can blow up a battery if there is a poor weld between cells. A short across the terminals can blow up a battery, just a spark can blow up a battery.

Don

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Reply to
Don

You have that right, I sure stand back when hooking up cables now and make sure a charger is 'off' before disconnecting or connecting it.

The caps were vented, so it was part explosion at least.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06
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Reply to
Mike Romain

you got that right on popping top of battery and it was cold when this happened when i jumped brothers camaro it was about 20 below lucky we never lost our eyes or eye sight.remember back in the day you could just pull up to where both bumppers touched for the ground???? just my opinion again....

Reply to
Scrapper

Sorry, I guess I should have specified these deaths as *at the time of the disaster*.

Oh, the humanity.....

Toyota MDT in MO

P.S. I heard that the working name for the Pinto during it's design phase was "Hindette" but it failed to rate well in early test marketing as the general public had no idea that this car was

*supposed* to catch on fire with regularity. Not completely related, but years later GM unveiled the X Body and gave it's highest selling version the name Chevette; the "ette" a tribute to Ford's Pinto project and it's clever, designed-in safety issues. It was the 1970's, and everyone wanted a small car that would blow up or crash easier.
Reply to
Comboverfish

and then came the pontiac t-1000 then the chevette back called a fearro i call it the backwards shitvette only difference from shitvette is motor in back...JUNK....

Reply to
Scrapper

Agree with every thing you say.

Mike's experience also makes me wonder if the very low temperature might have had something to do with it, for example cracking of the battery case, or such.

Back in the stone ages when I was taking mechanics courses, one of the first lessons that was hammered into us was not to wear watches or rings when working on electrical systems. I never forgot it. Recently saw some pictures of what can happen if your ring gets between B+ and ground.

Another picture I saw was what can happen if you get emotional or scared and get your ring caught. One of our company employees was petulant about something, slammed a file cabinet drawer, and somehow got her ring caught in it. She was left with nothing but a bone sticking out of her hand. No way surgically to repair the damage. Same can happen under a hood.

Reply to
<HLS

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