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Re: How do you test an alternator?
[Re: Fastback67]
#142615
10/29/08 10:14 AM
10/29/08 10:14 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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i wouldnt doubt that there could be momentary spikes but the wuation is , are they harmful to our cars.
The spike is probably a result of and instaneous change in the cirucit whether it be a lag in the VR compensation or some sort os charging effect. But even if there were 100v spikes, they are of what duration??? milliseconds? microseconds? how many amps? microamps? certainly not amps.
So there affect would be small because the average power or current delivered to the system would be negliable when you look at it real time.
its like the shock you get when you toch a door knob after rubbing your feet on the carpet. its several thousand volts BUT the duration is short (milliseonds) and the amps a low. so you dont die. Up the amperage or lengthen the duration and youre a dead man. you build up 50v of static charge just scratching your head- but you dont feel it.
on older cars with healty stought resistors and cap and maybe some power transistors (in the ign box or radio) they dont see that much average power. plus the resistance in the wires and the bleed offs from vraious power users drop that stuff into the dirt.
just a different persective
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Re: How do you test an alternator?
[Re: 5537SG]
#142617
10/29/08 11:14 AM
10/29/08 11:14 AM
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Joined: Jan 2003
Posts: 21,072
Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,072
Niles , Ohio
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Easiest way is get a test light.One end to ground and car off touch the large wire.If it lights it has batt volts.Now unplug the 2 wire connector and touch the large wire in it if the test lihjt lights its good.now turn on the key and touch the small wire if it lights its good.They have an internal reg.I used to rebuild those all the time at work.Super easy but for the prive of a reman not worth the effort.Id also check the actual volts with a volt meter also.But if you do the test Id say the alt is bad.That or just take it to a parts store and have them check it.Thats an easy alt to remove.Rocky
Chrysler Firepower
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Re: How do you test an alternator?
[Re: stumpy]
#142619
10/30/08 09:55 AM
10/30/08 09:55 AM
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Joined: Aug 2004
Posts: 5,033
Ontario
5537SG
super gas
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super gas
Joined: Aug 2004
Posts: 5,033
Ontario
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Quote:
"Its a practice that should have disappeared before leaded/regular gas."
Newer is not always the only way. The disconect trial has worked for a long time with no problems. I'm not saying your method is wrong but don't discount the old way either. Both work and I don't see one being any better than the other. The statement the "the spike didn't show any immediate damage but who konws what damage down the road" doesn't hold water. If it is going to cause damage it would do it right now not later. So I say let's just agree to do it our own way and go from there. I will continue to suggest the disconnect way and you can recomend your way.
Stumpy, the disconnect method never was, and never will be an accepted nor reccomended method of diagnosing a charging system. Its very dangerous for the persons performing it, and it can do serious damage to the car.
Doing damage now or later certainly does hold water. If you think it doesnt it only solidifys your lack of knowledge regarding electronics.
What if I took every second stud out of the walls of your house? Would it still stand? Im sure it would, but what would happen if you got a foot of snow on your roof? What Im getting at is that the damage (although immediate) may not present itself until later.
Im sure in all your years as a mechanic youve learned alot, and Im sure theres probably a thing or two you could teach me too, but when it comes to diagnosing a charging system, you need to learn the proper way.
You also need to stop reccomending disconnecting the battery with the car running before your advice seriously hurts someone.
Use a multimeter. Instead of grabbing a wrench to disconnect the battery, grab a meter and check the proper way. Just think, no matter what you determine by disconnecting the battery, youre going to need a multimeter for the next step ( determing if the alternator has all the correct inputs)...so just use the meter in the first place.
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Re: How do you test an alternator?
[Re: 5537SG]
#142620
10/30/08 10:23 AM
10/30/08 10:23 AM
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Joined: May 2003
Posts: 15,487
Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,487
Florida
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here is my "disclamer" what works for me...might not work for you so..is unplugging the vr on my dodge truck and shorting the one wire to make the alt go full charge to see if the alt IS capable of charging the wrong way too? been doing that just as long myself  
Last edited by scratchnfotraction; 10/30/08 10:27 AM.
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Re: How do you test an alternator?
[Re: scratchnfotraction]
#142622
10/30/08 10:44 AM
10/30/08 10:44 AM
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Joined: Aug 2004
Posts: 5,033
Ontario
5537SG
super gas
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super gas
Joined: Aug 2004
Posts: 5,033
Ontario
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Quote:
here is my "disclamer"
what works for me...might not work for you
so..is unplugging the vr on my dodge truck and shorting the one wire to make the alt go full charge to see if the alt IS capable of charging the wrong way too?
been doing that just as long myself
thats "full fielding" thats not really dangerous unless you left it like that for sometime.
disconnecting a battery is completely different. It turns a DC circuit into an AC one. Completely different scenario.
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Re: How do you test an alternator?
[Re: stumpy]
#142623
10/30/08 10:49 AM
10/30/08 10:49 AM
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Joined: Aug 2004
Posts: 5,033
Ontario
5537SG
super gas
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super gas
Joined: Aug 2004
Posts: 5,033
Ontario
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Quote:
As I said you are carried away with your method being the only one and I will still use and will tell others of my method. It has been an accepted method for a lot of years. Otherwise how come so many people know about it? I don't know where you got the idea that it is as dangerous as you claim it to be but experience tells me it doesn't happen like you want everyone to think. I won't argue with you any more because I can see you are too hard headed to allow someone else to have an opinion that disagrees with yours.
Im not the one hard headed here. Heres how willing I am to accept other methods...
diagnose it ANY OTHER WAY YOU WANT....but NEVER, EVER, disconnect the battery with the engine running on ANYTHING.
So, any other way you want. just not that way.
It has NEVER been accepted by ANYONE other than hacks and butchers. It certainly is not reccomended or accepted by ANY manufacturers or SAE service procedures. Not now, not ever.
why? because they understand what theyre doing.
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Re: How do you test an alternator?
[Re: 5537SG]
#142625
10/30/08 12:01 PM
10/30/08 12:01 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Quote:
here is my "disclamer"
what works for me...might not work for you
so..is unplugging the vr on my dodge truck and shorting the one wire to make the alt go full charge to see if the alt IS capable of charging the wrong way too?
been doing that just as long myself
thats "full fielding" thats not really dangerous unless you left it like that for sometime.
disconnecting a battery is completely different. It turns a DC circuit into an AC one. Completely different scenario.
explain the dc into ac situation? im unsure how that happens. are the diodes in the alt bypassed? is the current cyanging directions ever cycle? i cant envision this happening
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Re: How do you test an alternator?
[Re: stumpy]
#142626
10/30/08 12:28 PM
10/30/08 12:28 PM
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Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices
Why would you even post that?
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Why would you even post that?
Joined: Dec 2007
Posts: 7,759
So Cal
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Stumpy, the biggest problem with giving advice on the internet is you never know the situation on the other end. For example we do not know the condition of the battery, if it is deteriorated or sulfating excessively. Although highly unlikely things do happen! You never know how mechanically inclined or aware the person you are giving advice is.
I will have to agree with 5537SG. I'm never was a supporter of the remove the battery lead. If it does work for you great (don’t do it though), what I am more concern with is the safety aspect of it. I’ve been a working shop foreman/mechanic at small auto dealership for 15 or so years. In that time I can remember three times where an inexperienced tech have a battery explode in their face, and one time when an experienced tech had one blow up not in his face. So experienced or not it when there is a spark, explosions can happen!
Allen
Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first.
Life was a little easier when I was just a wrench.
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Re: How do you test an alternator?
[Re: stumpy]
#142627
10/30/08 12:33 PM
10/30/08 12:33 PM
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Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl
pro stock
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pro stock
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
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Don't mean to  , but here are just a few documents that should warn folks to be very cautious when dealing with batteries. http://www.aa1car.com/library/battery_safety.htm"WARNING: NEVER disconnect a battery when the ignition is ON, or while the engine is idling or running. Doing so can damage electrical and electronic components." http://ca.answers.yahoo.com/question/index?qid=20070222191231AAmSB9T"Do not disconnect the battery with the engine running, the resulting voltage spike from the alternator can fry all your electronics." http://www.engadineautoelectrics.com.au/battery%20care%20and%20maintenance.html"NEVER disconnect any battery terminals from a car's battery while the engine is running (to test if your alternator is charging, for instance). This could destroy your cars charging system and it's onboard electronics!" http://mypage.direct.ca/k/kdomries/safety.html"Batteries can explode. I didn't believe this until one blew up while I was connecting jumper cables to it. It made a very loud noise, and splattered battery acid all over the place, not to mention flinging jagged bits of plastic in all directions at very high velocity." http://www.loudouncountytraffic.com/2008/02/helpful-hints-for-changing-your-car.html"Don't disconnect battery cables while engine is running (your battery acts as a filter)." And for those that don't believe "harmless" static electricity won't do any damage, put on yer Hushpuppies, shuffle across the carpet and go work on your PC. 
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Re: How do you test an alternator?
[Re: Scott Carl]
#142628
10/30/08 01:05 PM
10/30/08 01:05 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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apples and oranges scott.
microciruits in NEW cars (note the word, NEW) can easily be damaged by the spikes. just like your PC can. but pre 1980's cars do NOT have those in them. Different result.
try blowing a tube from a 1950's TV by unplugging it. wont happen. too stout. they run on HIGH VOLTAGE HIGH CURRENT. do that to a microprocessor and you can kiss it goodbye.
DIFFERENT TECHNOLOGY
BTW, the batteries exploded because of the build up of flamable gasses which eminate from the battery. one spark and POOF. now, a car that is RUNNING typically have a FAN blowing which DISPERSES that gas so it DOESNT IGNITE.
Much like how gas stored near a water heater will explode- gas fumes are concentrated and not being blown and diluted but fart next to a bbq and no explosion cause the gas is diluted
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Re: How do you test an alternator?
#142629
10/30/08 01:29 PM
10/30/08 01:29 PM
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Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl
pro stock
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pro stock
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
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Quote:
apples and oranges scott.
microciruits in NEW cars (note the word, NEW) can easily be damaged by the spikes. just like your PC can. but pre 1980's cars do NOT have those in them. Different result.
try blowing a tube from a 1950's TV by unplugging it. wont happen. too stout. they run on HIGH VOLTAGE HIGH CURRENT. do that to a microprocessor and you can kiss it goodbye.
DIFFERENT TECHNOLOGY
BTW, the batteries exploded because of the build up of flamable gasses which eminate from the battery. one spark and POOF. now, a car that is RUNNING typically have a FAN blowing which DISPERSES that gas so it DOESNT IGNITE.
Much like how gas stored near a water heater will explode- gas fumes are concentrated and not being blown and diluted but fart next to a bbq and no explosion cause the gas is diluted
 You do have a point. Most of the hazzards relating to battery disconnection do pertain to newer cars with onboard electronics. 
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Re: How do you test an alternator?
[Re: Scott Carl]
#142630
10/30/08 02:46 PM
10/30/08 02:46 PM
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Joined: May 2003
Posts: 15,487
Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,487
Florida
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man I must be dumb... I have jumped cars,with # 12 wire and touching the bumpers together on the side the road,when every one said that ol hick trick wont work...was that bad for the car? undo the batt,swap them in out with the engine running in the rain,sure that was bad too! drove them around with no batt and never had any probs with them,then or later,that was bad also, right? so now I am a rabid redneck hack shade tree parts changer..got it it a dumb people method...best left to us dumb people to the OP,sorry your post got hijacked,hope you get it fixed,no matter which way you do it,like said...just trying to help... should have left that chivy post alone  ...my bad 
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Re: How do you test an alternator?
[Re: Scott Carl]
#142632
10/30/08 03:04 PM
10/30/08 03:04 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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(note to self- dont buy used cars from scratchin or scott)
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Re: How do you test an alternator?
#142633
10/30/08 03:24 PM
10/30/08 03:24 PM
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Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl
pro stock
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pro stock
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
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Quote:
(note to self- dont buy used cars from scratchin or scott)
 .... ..... ....
......  .......
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Re: How do you test an alternator?
[Re: Scott Carl]
#142634
10/30/08 03:39 PM
10/30/08 03:39 PM
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Joined: May 2003
Posts: 15,487
Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,487
Florida
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for sale 440 max wedge hemi with a stock 3/4 cam and no alt/charging system gots a cut off switch in the trunk missing some of the factory smoke that comes in the wires in the dash,they got a leak when I tested the alt the lights are dim cause its low on the blinker fluid in the master cyl bring your own batt,mine is blowed up,sorry its on a hill,I will help push you down it to pop the clutch on the auto tranny BR549 I have a car for you! note to myself...undo the batt when running and drive it home tonight,I will post back if it leaks any smoke out 
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and