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Bad AMP Meter ?


James_Douglas

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Sorry James..as everything is going through your amp guage then I am like you, totally at a loss for the erratic action..I had specifically asked that questione arlier and did not get an answer..otherwise I would not have posted the possibility of connecting straight to the battery..I made that comment because most sites that reference installation of a 1 wire recommend to connect direct to the battery. Hope it did not rufle feathers...was not my intent...the one site I referenced talked about a very similar erratic action.

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Tim,

This NOT correct. I have the one wire connect directly to the original black wire that used to attach to the BAT terminal on the original voltage regulator. The other end of that wire goes directly to the AMP meter.

James

James;

Are you sure?

That is how I have my alternator connected. However not everything from the black wire that used to attach to the BAT terminal on the original voltage regulator goes directly to my amp gauge. There are a few more wires coming out of that bundle as shown in this picture (the bundle in front of the starter solonoid switch). I really need to re-wire my car. When I turn on my headlights my amp gauge does not jump as it does when I turn on my radiator fan. My fan is wired through my ignition switch. My lights are not wired through my ignition switch as they will come on with the ignition switch off. Bet your car is the same. The drawing Tod posted explains why. My battery stays charged. Does yours?

vasres11.jpg

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. . . My battery stays charged. Does yours?. . .

James has an Optima battery which means he can't just check the electrolyte density to see if it is properly charged. I guess he could check with a sensitive voltmeter if the battery has the proper value for the float charge on a lead-acid battery but that would, I think, require he disconnect the battery from any possible load. And the few 10ths or 100ths of a volt difference between the float voltage and not would be too small to detect on any volt meter I own.

Based on James' experiences I think I will never get an Optima battery. I get good reliable known life out of inexpensive off the shelf lead-acid batteries. And I know how to check them with simple tools to see if they are in good condition.

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Don & Tod,

The power wire to the headlight switch on my car is connected to the AMP gauge. I am not sure, but I think it is on the opposite side of the wire coming from the alternator.

Question: Since the alternators are self energizing...If you pull the battery cable, will the field collapse in the alternator and the thing stop putting out power and cause the engine to die ?

James

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Don & Tod,

The power wire to the headlight switch on my car is connected to the AMP gauge. I am not sure, but I think it is on the opposite side of the wire coming from the alternator.

Question: Since the alternators are self energizing...If you pull the battery cable, will the field collapse in the alternator and the thing stop putting out power and cause the engine to die ?

James

In theory you can disconnect the battery and everything should still run off the alternator. As I recall, Chrysler did a promotion of their then new alternator (industry first) by starting a car, removing the battery, then driving it cross country. This is something you can't do with a generator as the idle output is too low to keep the engine running especially if you have the lights on.

Note: Don't try disconnecting the battery on a 1920s or 1930s car with "third brush" regulation of current. You will fry the components in your electrical system.

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In theory you can disconnect the battery and everything should still run off the alternator. As I recall, Chrysler did a promotion of their then new alternator (industry first) by starting a car, removing the battery, then driving it cross country. This is something you can't do with a generator as the idle output is too low to keep the engine running especially if you have the lights on.

Note: Don't try disconnecting the battery on a 1920s or 1930s car with "third brush" regulation of current. You will fry the components in your electrical system.

Tod,

I am not so sure. In my 1-wire set up the only thing keeping the stator energized is the power flowing through the battery. When you take a cable off the 1-wire alt. the stator magnetic field will collapse and the voltage will go to zero.

This is what I think vs. what I know for sure. I will make a couple of calls to find out.

Now, if you wire it up as a "3-wire" alternator, then the wire that normally makes it excite as soon as the ignition is turned on will, I think, feed the voltage to the stator from the alternator output even when the battery is out of the circuit.

Again this is an "I think" not a I Know" kind of thing.

James

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Don & Tod,

The power wire to the headlight switch on my car is connected to the AMP gauge. I am not sure, but I think it is on the opposite side of the wire coming from the alternator.

Question: Since the alternators are self energizing...If you pull the battery cable, will the field collapse in the alternator and the thing stop putting out power and cause the engine to die ?

James

James;

Best keep Tim Adams in this loop as his knowledge on electronics and car electricals far exceeds mine. He is just too nice to smack you alongside the head when you need it. As I have said I am on the road and cannot do any live tests. However your live test should be to see what is energised with your key off. Having given this a nights sleep I believe eveything that is alive with your key off is not going through your amp gauge same as my car is wired..

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James;

Best keep Tim Adams in this loop as his knowledge on electronics and car electricals far exceeds mine. He is just too nice to smack you alongside the head when you need it. As I have said I am on the road and cannot do any live tests. However your live test should be to see what is energised with your key off. Having given this a nights sleep I believe eveything that is alive with your key off is not going through your amp gauge same as my car is wired..

Hey, I like a slap in the head so EVERYONE please slap me when (not if) I have my head up my #$%$^.

In the AM I am going to take my NOS amp meter and add a couple of wires to it. I am going to connect it in series to the battery positive cable. I will not try to start the car this way...

I will then turn on every electrical device. I will then note what the NOS gauge shows, whet the in-dash gauge shows, and what the Fluke clamp on meter shows.

I will also do it one device at a time an make a note of it.

James

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Well, heres is a short Everything you wanted to know about Gennerator and alternators. There are several wiring diagrams which may or may not help this discussion. The remote voltage sensing circuit may be of interest. Also the section regarding the idiot lamp is interesting in that it discusses the situation where the voltage at the battery and the voltage at the alternator are the same and the sytem is balanced so there isn't a need for much to be goin on and the internal regualtor acts to drop the alt out put to match the system need.

There is also a couple of sentences regarding a slight ignition off draw by single wire alts.

I don't know if this is revelent but here is what the wiring schematic for the Studebaker shows. Bat terminal to ammeter of this ammeter post a wire goes to the ignition switch (I believe this is the power in to the switch), a second wire goes to a 30 amp circuit breaker. The circuit breaker feeds the head lamp switch. (there is no heater or other accessories shown on this chart) The output post of the ammeter connects to the battery side of the solenoid.

This site refers to GM alternators and shows 3 or 4 wiring schematics that may be helpful.

http://www.rowand.net/Shop/Tech/AlternatorGeneratorTheory.htm

and some more as referenced from the above site;

http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

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It is difficult to "head slap" one suffering from "endorectalcervisitus". This refers to an irratation of the neck resulting from having ones head up one's butt. There is also "ectorectalcercisitus" which result from having one's head up someone else's butt. That is usually seen in office settings.

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It is difficult to "head slap" one suffering from "endorectalcervisitus". This refers to an irratation of the neck resulting from having ones head up one's butt. There is also "ectorectalcercisitus" which result from having one's head up someone else's butt. That is usually seen in office settings.

Yep Greg, ur right about the inability to headslap in those cases.... would be called a spanking... :D

Allan

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Ok Guys, This is what I think is going on.

Prior to any work on the car last month the AMP gauge would show a fairly good positive flow, when driving down the street, when I had any of the big current items on like the headlights, the radio, or the duel fans.

It would also show a good negative flow when the engine was off. I had not studied the wiring diagram I have in detail to see that many items a common off of the Alternator side of the AMP gauge as has been pointed out.

Over the last month I took out the M5 transmission and its associated electronics and replaced them with the 3-speed and its associated electronics. I also removed the entire dash cluster. I took apart the cluster and cleaned and tightened down all connections. I also added a #8 wire to the wiring harness that runs directly from the case of the alternator (ground) to the dash to make sure that the dash items have a good ground path back to the alternator.

What I am surmising is that prior to this past months work that something was amiss. I think that something that was causing current to be pulled from the battery, and hence across the AMP gauge, and not from the alternator.

Once I cleaned and tightened everything, the alternator was able to provide all necessary current and so there is no draw on the battery when running.

As per instructions on the Delco site, I disconnected the ground battery cable and I hooked up my NOS AMP meter in series. I then turned on each device one at a time and wrote down the current draw. I noted the NOS gauge sitting on the fender, the gauge in the dash, and the reading from the Fluke tester with the DC clamp.

BTW, here are the results:

Headlight (Hi) Inside-19, Fender-15, Fluke-15

Radio (With XM & Transmitter) 11, 9, 10

Duel Heaters 19, 11, 12.8

Spot Light 5, 4, 8 (I suspect this may be wired to the BAT side)

Wipers 11, 9, 9.5

Radiator Fan 9, NA, 16 (This uses a relay)

One interesting thing is that Delco says to add everything up and add that Alternator load should be 50% greater than vehicle load requirement. Given that math I should have about a 115 to 120 Amp alternator.

When I ordered my alternator, I looked at the Amp gauge and figured that since it showed a 35 AMP max charge that that was the max load on the car. I am obviously wrong. I ordered a 40 AMP alternator (6 volt Positive Ground) based on that bad logic.

So at an idle with everything idling it is little wonder that I can kill the engine as the alternator can not keep up. So, I will order a 125 AMP 10SI and put that in.

Live and Learn.

Best, James

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