9/11/00 - Using the body of the car is a bad idea, I was mistaken about the engine. I guess I forgot to think about the fact that the spark plugs wouldn't work if the engine couldn't be used as ground.

I might be totally wrong on this, so please correct me if I'm mistaken.

I've read somewhere that the F150's have a filtered electrical connection between the body and the negative terminal on the battery to prevent interference on the radio. If we use our trucks to jump or be jumped, we have to connect the cables directly to the battery to prevent damage to the filter. Is this true?

[This message has been edited by michael_hovis (edited 09-11-2000).]

 

Well, the owner's manual for my '99 seems to suggest otherwise. Under Roadside Emergencies section, step 4 under Jump Starting says, " Make the final connection of the negative (-) cable to an exposed metal part of the stalled vehicle's engine, away from the battery..."

 

I assume you know why you *should* use the body or the block as a ground. For those who don't, well, it's for a very good reason. If the battery has a failure inside,(shorted plates, etc.) and you hook you a fully charged battery to it, the bad battery can explode. Most likely when you are attaching the cable to it. Not a pretty sight. You should also hook the ground on the dead battery up last, that way, no sparks are generated at the battery. I use the engine hoist pieces to ground to usually. It amazes me people who do it everyday (towing, repair guys) are so casual with electrified acid I sure it's because it's takes a little longer to charge if you aren't hooked up directly to the terminal. I guess it takes seeing one of these things explode to believe. Just a word to the wise.

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[This message has been edited by 2000 F150 4x4 (edited 09-06-2000).]

 

2000 F150 4x4,

Thanks for the explanation. I won't ever forget now. I've never seen one blow up. Saw a gas station blow up once, though. Terrible sight; not like the movies.

 

Here's my .02 to help cloud the issue... the issue with sparks is thus: A discharged battery gives off flammable Hydrogen (Can you say, "Hindenburg?") The hydrogen explosion is what causes the battery to explode. The spark could potentially occur within the battery case if it were shorted internally. Given that the final connection is going to spark a little bit (it's unavoidable) you want to make that final connection where there is the least chance of igniting a flammable gas: under the hood of a running engine with a fully charged battery! (Air-flow from the fan and a full-charge on the battery) Given those conditions, here's the process I follow each and every time:
1) Connect the Positive cable to the positive terminal on the good battery.
2) Connect the positive lead to the positive terminal of the dead battery.
3) Connect the negative cable to the negative terminal of the dead battery
4) Make the final connection of the negative cable to a chassis ground on the vehicle of the good battery.

This process generates a spark somewhere away from the battery of the vehicle least likely to have a hydrogen cloud in the first place. Plus, if the dead battery should happen to explode for some reason, you are(generally) facing away from it at least a few feet away, further reducing your chances of serious injury.

Well, that's my story and I'm sticking with it.


Now, as for the original question... I believe that most noise filters are a simple capacitor... not going to be hurt by axcess current through the leads. Otherwise, how would you start your car without destroying it? (Your starter is a chassis-ground too)

-Joe-


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98 Explorer (Lemon Law Case in Progress)
Deposit on '00 F-150, X-cab, 4x4, Lariat, Off-road, Trailer Tow, Sunroof, currently missing the fuel filler door, but they're working on that..

 

Actually, there's more hydrogen around a charged/charging battery than a dead one. Two parts hydrogen and one part oxygen is produced when a battery is being charged.

Having said that, you should be aware that the atmosphere inside the discharged battery should be the hydrogen/oxygen mix unless the battery has been discharged long enough that the normal atmosphere has entered and pushed out the explosive gas mixture.

Pure hydrogen just burns in the presence of oxygen. When you have a mix of 2 parts hydrogen and 1 part oxygen, that mix is explosive. Ignite a balloon filled with pure hydrogen (as the Hindenberg was) and it will go whoomp. Ignite a balloon filled with two parts hydrogen and one part oxygen and it will go KABOOM.

The procedure to jump start a vehicle that's described in our owner's manual seems to be the industry accepted standard. At least, it's the same procedure that I've seen described over and over in various publications.

An exploding battery is no fun. Had one explode while starting the '87 a few years ago. It sounded like a bomb and brought the neighbors out of their houses. Electrolyte was sprayed all over the engine. Luckily, the top of the battery was held down by the clamp. I have no doubt, it would have damaged the hood if the clamp didn't hold.

 

Dennis, sounds like you've had the chemistry class demonstration done all over the world. I had mine in my 2nd quarter at the U of MN, shook the chaulk off the boards.

I can't for the life of me remember where I read that. I know that the last connection should be the negative side of the discharged vehicle side to the engine ground.

Maybe it was not to use the body as a ground. Yeah! That's it. I must've read somewhere not to use the body as the ground because the filter was attached between the body and the engine ground. I think it was more than a capacitor, though. Ah well, maybe I can actually find the text.

 

Michael,

Actually, none of my profs ever did that demo. It was assumed, I guess that we are supposed to know these things by the time we were in college. One day, while I was in the organic chem lab, we heard a KABOOM that literally shook the building. We evacuated the building thinking it was a bomb. LOL.

A new prof did the experiment for one of the lower level chem classes.

 

Whilst topping off the oil after a filter change, I noticed the small ribbon-like wire between the body and the engine. I think this is the wire I read about. If you open the hood, you'll see it connected below the left-center of the windshield to the top of the engine. This wire would definitely fry if you tried to ground a jump-start to the body of the car.

 

I'm guessing about why you're not supposed to make the final connection at the charged battery.

First off, I think for safety reasons, you should not have the engine running while you make the initial hookups at the charged battery. While the possibility of having hydrogen gas built-up around the battery is slim, I'm sure there is still a possibility.

Second, and I think a more plausible reason, is the chance of an internal problem in the charged battery causing an explosion. The reason I thought about this is because of my experience with an exploding battery when starting a vehicle a few years ago. Jumped in the old truck one morning, turned the key to start and Kablooey.

Was told that the reason a seemingly good charged battery explodes when you try to start the engine is because a fault inside the battery caused an arc inside the battery which sets off the hydrogen/oxygen mix. This arc is caused when you put a heavy load on the battery.

So, I'm guessing that if you make the final connection at the charged battery, the load of the dead battery just might be enough to cause an explosion like I experienced. It's a remote possibility, but an exploding battery is not a pretty sight. I have no doubt if I was standing near an open hood and had a battery explode, I'd be drenched with electrolyte at best and would be going to the hospital with a concussion or impalement at worst.

 

OK, well, point being don't use the body as a ground. It's all grounded for noise supression... I suppose grounding to the body might damage this thin ribbins, but to the block or frame I'm sure wouldn't be an issue. As for the hydrogen issue... point being that you want to generate the spark at the final connection in an area least likely to have a hydrogen build-up... my personal opinion is that under the hood of a running vehicle with a fan moving volumes of air (and probably just recently driven over to help the stranded vehicle) is less likely to have any hydrogen built-up around the battery and under the hood than one sitting stationary and not running. I suppose it might be trivial, but again, you're facing away and located a few steps away from the battery with the higher potential for explosion when you make the final connection on the good vehicle's chassis. Just my .02, though.
-Joe-


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98 Explorer (Lemon Law Case in Progress)
Deposit on '00 F-150, X-cab, 4x4, Lariat, Off-road, Trailer Tow, Sunroof, currently missing the fuel filler door, but they're working on that..

 

So where do you guys usually ground your power to on the vehicle with the dead battery? I mean a specific point. Not like the block or the body but where exactly do you ground it to?

 

"hello Ford Roadside assitance?. Yeah Hi, I need a no charge boost thats included within my 3 yr warranty""

 

A friend of mine had a Battery blow up in his face. He was working a student summer job on a ferry when he was helping to boost a car that would not start when the ferry arrived. Sulfuric Acid went up his knose and he lost all his sense of smell and most of his sense of taste.

Although, strangely enough, he gets a funny taste in his mouth just before we get a lighting storm. He says it tastes like that funny tast that you get on a fork when you rub the fork on foil paper back and forth.


BTW, For ground, I did not yet need to look for a place on the truck, but on many vehicles, I use the Alternator mounts.

Dpostman

 

Very well Sir, what is your location?...Oh, alright. Our crews are busy at the moment and I will dispatch a truck as soon as one is available, it shouldn't be more then six or seven hours.