New way to Jump Start a CAR?!?!

[latest-good]

Hello,

I always learned that your supposed to ground the negative on the stalled car when jump starting a car. Well, a mechanic told me that it's better to just clamp (+) and (-) on the good battery and dead battery. He told me I don't have to ground the stalled car. Why is that? How come I've always told to ground the stalled car?

[UncleBob]

urrr...."ground" (aka, chasis or engine ground) is grounded because the negative battery cable connects with the chasis and engine. When you ground it on the chasis or engine, you're only adding to the path to the battery.

Nothing wrong with doing it that way, assuming you have good cables and connections....but assuming the battery negative is easy to get to, it makes more sense to put it on the battery instead.

[72chevelleOhio]

Originally Posted by UncleBob

Nothing wrong with doing it that way, assuming you have good cables and connections....but assuming the battery negative is easy to get to, it makes more sense to put it on the battery instead.

I think he means that stuff (b.s.?) about having the ground be the last connection and it "has to be" on something other than the battery itself, to prevent an "explosion" or a "fire hazzard" due to the battery fumes or something? Never had it happen, or heard a story about it happening to someone, so I don't remember exactly...now while charging the battery and have it explode, thats another story..

[curtis73]

The "proper" way to do it is to connect positive and negative to the helper car, and connect positive on the dead car. Then the last connection should be to a ground on the dead car. The theory is that batteries (since they produce hydrogen gas) can be explosive if you cause a spark near the battery. So the last connection (being the only one that causes spark) should be away from the battery.

I try to adhere to that philosophy. I had one battery explode on me. It wasn't a jump start situation, but the alternator wire fell onto a valve cover bolt, welded itself tight, and the battery started boiling and spewing sulphur dioxide and hydrogen. I ripped the wire off and the resulting spark ignited the hydrogen. Fortunately I got out of the way, but my freshly painted fender was toast.

Its one of those things that would happen one out of a million times, but considering that the accident involves acid exploding on your body, it bears some consideration.

[72chevelleOhio]

Originally Posted by curtis73

.. It wasn't a jump start situation, ..

Thats what I was talking about. I never heard an actual case of someone blowing up a battery when hooking up jumper cables, just that it was possible, so its recommend that a "remote" ground be used.

['97ventureowner]

Originally Posted by 72chevelleOhio

Thats what I was talking about. I never heard an actual case of someone blowing up a battery when hooking up jumper cables, just that it was possible, so its recommend that a "remote" ground be used.

Here is an actual case of someone that blew up a car's battery. I met this guy who was a friend of one of our customer's who came into the shop one day. I notice his face was disfigured and his friend told me that one day he stopped to help a person who's car had broken down on the highway. He proceeded to jump start her car when the battery exploded, spewing battery acid all over the place including the guy who had stopped to help.He suffered burns all over the front of his body leaving him disfigured.
Kind of sucks to be a Good Samaratin and stop to help somebody in need only to end up having something like this happen and to have to live with it the rest of your life.

[UncleBob]

as a general rule, if you smell a strong odor of sulfur.....don't jump it.

[bobss396]

I was taught to attach the ground cable to the "dead" car last and always to something other than the battery. This eliminates or lessens the probability of causing a spark and in some cases makes for a more accessible and better ground.

I've also seen someone jump a battery with ONE cable. This is back when car bumpers were all made of steel. Attach the positive to positive cable, touch bumpers and give it a start!

I've seen batteries blow up in shops. One was sparked by the hood latch being opened, as soon as the guy opened the hood it blew. But he should have known better because the car reeked of sulphur as soon as it pulled into the bay. Luckily he was ok and had an emergency room trip to rinse his eyes out and patch up some minor cuts. We did have a big sink close by with a shower head on the faucet and practically drowned him.

From that day on, cars with batteries like that we're left outside and we made up a plywood shield so we could open the hood safely. From there, taking the battery out was a 2-man job, one held a hose with running water over the battery, the other took the battery out.

Bob

[KiwiBacon]

Originally Posted by curtis73

I had one battery explode on me. It wasn't a jump start situation, but the alternator wire fell onto a valve cover bolt, welded itself tight, and the battery started boiling and spewing sulphur dioxide and hydrogen. I ripped the wire off and the resulting spark ignited the hydrogen. Fortunately I got out of the way, but my freshly painted fender was toast.

It's crap like that that led me to wire in lock out switches on each battery in my 4wd. I can't remember exactly what was shorting, but the time it took me to pull a battery lead was way too long (probably half a second, but felt like 10).

Now I can flip a switch and remove either or both batteries, even while the vehicle is running without worrying about stray leads. Makes jump starting others nice and easy too.

[bobss396]

I used to run a battery lockout on my stock cars before it was mandatory. I also add them to any hotrod work that I do.

Bob

[j cAT]

never jump or charge a dead battery left in freezing temps..... the vent holes can be plugged and then the battery will explode throwing acid all over ...........