Batterie wont charge-very complicated

[j cAT]

Originally Posted by MobileMom

I will admit that there are risks with pulling the battery cables off with the car running, however, in my experience, and I have done this with more than 20 vehicles, it will do nothing more than tell you whether you have a bad alternator or a bad battery. I learned this trick from a mechanic with more than 50 years experience, and have seen it done by other long time mechanics.

Not to mention, Guys, just because you don't agree with my techniques, does not mean you need to start bashing my post. Just put up what you feel the dangers are, or what ever you feel would be better. This forum is to answer questions to the people who asked the question, not a forum to beat down other posts.

this quote of removing the battery while the engine is running is very bad advice .... now this is not my opinion but the opinion of MR. GM and in the shop manuals this is described as how to damage your vehicles computer....so if you would rather buy a computer for you vehicle instead of purchasing a good volt/ohmmeter that will be your choice......the old timer that suggested this faulty advice was pre computer like before 1975.....

[j cAT]

I would check the big wire from the alternator to the battery +. If the field wire is bad, the alternator will overcharge, not undercharge. Higer voltage input tells the voltage regulator to lower the output. Lower input tells the regulator to increase output. If the field wire was bad, your battery would be boiling over.

quote]

jr you are wrong about the field wire removed causing the alternator to increase output.....just disconnect the small wire start engine an you will see no output from alternator..... this voltage/power creates the magnetic fields required to generate electricity....

[j cAT]

Originally Posted by curtis73

He's right... they're all techniques that work regardless of whether or not you like them. Be nice, don't discredit. Discuss, don't degrade. Peace, not war, man.

if you post damaging advice,and advice that can cause personal injury it must be corrected immediately.....if your feeling are hurt so be it.....

[hueroloco]

I've been a tech for 20 years and my input on the whole taking the battery cable off is that it works. I've never seen it damage anything. It is kind of ridiculous if you have a voltmeter to use, so I wouldn't ever do it. But I've heard of backyard mechanics doing a lot worse.

[j cAT]

Originally Posted by hueroloco

I've been a tech for 20 years and my input on the whole taking the battery cable off is that it works. I've never seen it damage anything. It is kind of ridiculous if you have a voltmeter to use, so I wouldn't ever do it. But I've heard of backyard mechanics doing a lot worse.

my problem with this is so you damage your computer it cost some cash to fix and you move on...... it's when the explosive gases generated by charging discharging get ignited by the arcing, and then your blind,thats when you don't move on it's all over for you....so i don't want anyone to get injured .........

[J-Ri]

I too did not intend to insult the post nor the poster, but thought a warning (like those found on the big orange tags that come twisty-tied to the new alternators) was needed about disconnecting the battery while the engine is running. I appologize if my words were taken as an attack.

Originally Posted by j cAT

the old timer that suggested this faulty advice was pre computer like before 1975.....

Disconnecting the battery can create a voltage spike which can take out today's sensitive (and expensive) computers. I have also heard (but not read, in any reputable publication) that the voltage spike can damage the alternator as well.

[MobileMom]

Well... 72 chevelle, thank you for noticing on the female thing. Not that I feel it makes all that much of a difference. Knowledge is the key here.

Now, I believe your question is based around what I said about an older alternator belt stopping the alternator from charging.

Logically, I would agree that as long as the belt is tight, it should never stop the alternator from giving the battery a charge. However, If you have been a mechanic for a while, you might have noticed that every fix is not always a logical fix.

I have had only a small percentage of the vehicles that I have worked on, have a charging problem because of an old belt.

I would personally check all other options first, i.e. timing, wires, connection, volts, etc...

But if nothing is working, there is no reason to rule the belt out. If it is old, it is probably also dull and not gripping the alternator the way it should, or the fan pully, which would cause it to slip, which would make it harder and harder for the alternator to get a charge, because it needs to turn to do that.

Thats the most logical answer I can give for why an old alternator belt would stop it from charging. It is weird, and I am more than willing to admit that it is not logical, but it happens.

I also took the time to look up the truck in Chiltons Manuals, and it says:

Troubleshooting Basic Charging System Problems
Problem Cause Solution

Inidicator light is on or *Broken Belt -Install Belt
amp meter reads a discharge *Broken or disconnected wires -New Wiring
*Internal alternator problems -Replace Alternator
*Defective Voltage Regulator -Replace Regulator

Low Voltage Output (alternator *Loose or worn Belt -Replace or adjust
lights flickers constantly or amp *Dirty or Corroded your belt
meter wanders) Connections -Clean or Replace
*Internal Alternator or connections
Regulator problems -Replace alternator
or Regulator


Now, Chiltons isn't the bible or anything, but they have spent years trying to help do-it-yourselfers for years. Even they say that a charging system problem can be cause by a loss or worn belt.

Besides, a new alternator would cost all of 10 bucks, probably not even that, and if it wasn't the problem, it wouldn't have broken the bank.

So it wouldn't hurt anything to rule out the belt as an issue, right?

As for my methods of removing the battery cables while the truck is running..... I do agree that on a newer vehicle, you would have issues with any onboard computer. However, up until around 1996, they did not have computers that blew up when you unhook the battery cables with the engine running. Not to say they did not have computers, or ECU's, but they were just not as sensitive as the vehicles we see today.

The mechanic who showed me this trick was an old timer, and there is nothing wrong with that. The test should always be a last resort test. Most people today can go down and buy a multi-meter and there is no reason to do this test unless you can't think of anything else. It is a very "Backyard" thing to do, but when you need to think out of the box, its there, and it has worked for me on more than enough vehicles, and I have never once blown up a battery with it, seized the alternator, or caused any damage to an onboard computer.

However, I do not want to discredit any of you guys who gave warnings such as those. An important thing to remember when your doing any work on your vehicle yourself, especially with the electronics, you want to be CAREFUL.

I also want to say again that if you have jumped your car to start more than three times in a WEEK, you can kill your battery or alternator, even if they are brand new, and your starter will be next.

Remember: If you are working on your own vehicle, nobody but you will be responsible for what you do to it. And any mechanic will charge you more if you make the problem worse. So, whether it be my advice or anyone else's who does not give you a warranty with that advice, you run the risk of making your problem worse. If you feel that you can't do the job right yourself, it is best to find a shop that you trust to take a look and tell you what you can do, or have them do.

Thanks

[MobileMom]

I apologize on the part I tried to copy from the Chiltons manual. It did not come out the way I was hoping it would, but I hope you get the jest.

[Moppie]

Originally Posted by MobileMom

I do agree that on a newer vehicle, you would have issues with any onboard computer. However, up until around 1996, they did not have computers that blew up when you unhook the battery cables with the engine running.

Maybe pre-96 American computers are simpler than those found else where (punch cards are pretty fool proof) but I know of plenty of 1980s era cars that have suffered ECU damage because of voltage spikes from battery's being disconnected etc.

[72chevelleOhio]

Originally Posted by MobileMom

If it is old, it is probably also dull and not gripping the alternator the way it should, or the fan pully, which would cause it to slip, which would make it harder and harder for the alternator to get a charge, because it needs to turn to do that.

Okay, terminalogy. When you say "old", it should be taken as "worn".....I agree that a worn belt will slip and cause problems, a lot of the time accompanied by squealing.



Just call me the the grammer police, everyone needs to choose their words carefully (or at least reminded to)....If any of that is not spelled correctly, or anyone don't like it...."below me"

[j cAT]

Originally Posted by MobileMom

As for my methods of removing the battery cables while the truck is running..... I do agree that on a newer vehicle, you would have issues with any onboard computer. However, up until around 1996, they did not have computers that blew up when you unhook the battery cables with the engine running. Not to say they did not have computers, or ECU's, but they were just not as sensitive as the vehicles we see today.

The mechanic who showed me this trick was an old timer, and there is nothing wrong with that. The test should always be a last resort test. Most people today can go down and buy a multi-meter and there is no reason to do this test unless you can't think of anything else. It is a very "Backyard" thing to do, but when you need to think out of the box, its there, and it has worked for me on more than enough vehicles, and I have never once blown up a battery with it, seized the alternator, or caused any damage to an onboard computer.


Thanks

I can't believe this! you insist on this practice of removing the battery leads while the engine is running..... Now if anyone wants battery acid over their body, eyes, and acid and plastic imbedded in their face

this is how to do it!

[J-Ri]

Originally Posted by MobileMom

Besides, a new alternator would cost all of 10 bucks, probably not even that, and if it wasn't the problem, it wouldn't have broken the bank.

I think we found the reason the alternators are lasting 4 years

I agree that most of the time disconnecting the battery won't hurt anything. If you did it 1,000 times, you might have a problem once, maybe only 1 in 10,000. I sure don't want to replace a part that wasn't bad or explode the battery when the terminal arcs and ignites the hydrogen, even if it only happens once. If no voltmeter is available, turn the headlights and dome light on with the engine running. Shut the engine off and watch the dome light (headlights are to quickly remove the surface charge on the battery to make the transition from ~14V to ~12.5V quicker [and therefore easier to see], could also use any other load). If the lights dim, the alternator is charging. If they don't dim, the alternator is not charging.

[MobileMom]

My apologies, thats what I get for posting late night. I meant an alternator BELT for 10 bucks or less.

Yes, you can all laugh and have your way with my typos. I think anyone who is truly looking for the knowledge will know what I meant.

[72chevelleOhio]

Are you kids done hi-jacking the thread already?

Start over from here.....

Originally Posted by jon_tstc2000

i have come to the conclusion that the gauges is what the problem is. the gauges are out of a erlier truck. the brown wire that comes from the gauges to the altinator has no power at all. the power wire going to the gauges is hot but coming out to the altinator its no good.

Other then the typo's whats wrong here????....