Simple midyear question.

[KOPBET]

So the #2 sense tab is connected to the horn relay and #1 field tab is switched through the ignition and the idiot light? BATT is routed through the ammeter to the battery + ?

 

[bossvette]

FWIW
On older hot rods I have built with big motors and added electrical goodies I have used a ford type solenoid mounted on the firewall to cure the "hot start" blues. This also serves as a distribution point for added accessories that do not need to be switched. To ease wireing I use a 1 wire alternator. The "accessory feed" or #1 wire can then be used to control the relay for the fan so it shuts off when the ignition is shut off.
Now a days you can even buy a kit to do this, but I have been doing it for years.:L

 

[67HEAVEN]

So the #2 sense tab is connected to the horn relay and #1 field tab is switched through the ignition and the idiot light? BATT is routed through the ammeter to the battery + ?

Midyears don't have idiot lights, except the one shining over the driver's head when I open the door.

 

[KOPBET]

Midyears don't have idiot lights, except the one shining over the driver's head when I open the door.

Well, I've never had the pleasure ... :cry

And the other questions? :W

 

[67HEAVEN]

So the #2 sense tab is connected to the horn relay and #1 field tab is switched through the ignition and the idiot light? BATT is routed through the ammeter to the battery + ?

Now we're getting into a stock versus modified scenario. The stock setup included a 4-wire alternator and an external voltage regulator (4 connectors), while my current 3-wire alternator has an internal regulator and aftermarket jumper assembly to bypass the old external regulator, (which I left in place to fool the judges).

Further, I'm not using the original TI module, distributor, nor coil, so the wiring is further changed from stock.

The ammeter was, and is, routed to the starter solenoid (thus BATT+) and the horn relay.

:crazy

My head hurts.

 

[67HEAVEN]

Well, I've never had the pleasure ... :cry

KOPBET,

Here's a photo to help keep you happy until you do....

 

[KOPBET]

Now we're getting into a stock versus modified scenario. The stock setup included a 4-wire alternator and an external voltage regulator (4 connectors), while my current 3-wire alternator has an internal regulator and aftermarket jumper assembly to bypass the old external regulator, (which I left in place to fool the judges).


My head hurts.

Actually I wasn't. I didn't really care what the stock setup was, I was more concerned with what you have now. Sorry I made your head hurt. :crazy

With the internal regulated alternator it would seem that the premise is exactly the same, except the location of the regulator has moved. Since there's no functional difference between a four wire and a three wire alternator, all you have really done there is eliminate a ground wire.

It seems as though the internal regulator is kaput.

From what you describe, that would seem contradictory to me. You are at 14.2 volts. If the voltage regulator was bad, I would think that the output would be either well above 15v or nothing.

The ammeter was, and is, routed to the starter solenoid (thus BATT+) and the horn relay.

If this is the case isn't the the ammeter is between the + source and a load point? You would always have current here (i.e alternator output current), would you not? If you wanted zero out (no battery charge current) on the ammeter, wouldn't you want it between the alternator output and the battery (solenoid +)? My brain hurts. :crazy

KOPBET, Here's a photo to help keep you happy until you do....

Thanks for sharing that! I'll leave you alone now.

 

[Mac]

From what you describe, that would seem contradictory to me. You are at 14.2 volts. If the voltage regulator was bad, I would think that the output would be either well above 15v or nothing.

Another link to the MAD website... this one about Regulators which uses an excellent analogy to describe the relationship of alternator, regulator and battery. An alternator can't produce more voltage than it was designed to produce but it can push continually push more amperage than is necessary to maintain the system. The battery acts as a buffer but continual overcharging will damage it.

-Mac

 

[KOPBET]

Another link to the MAD website... this one about Regulators which uses an excellent analogy to describe the relationship of alternator, regulator and battery. An alternator can't produce more voltage than it was designed to produce but it can push continually push more amperage than is necessary to maintain the system. The battery acts as a buffer but continual overcharging will damage it.

-Mac

Nice link, thanks.

However, I believe your interpretation is wrong. You cannot change Ohm's law. Additionally, the alternator cannot "force" out more amperage that the system will use. More Ohm's law. To quote your link:

"If the alternator was allowed to constantly produce all the power it could, system voltage would rise to a damaging level, the battery would overcharge, components would be damaged, and the alternator would soon overheat and burn out."

Again:

"(No matter how powerful the alternator, output is limited according to system demands.)"

This says that the system voltage will rise to an unsafe level. In Bob's case this does not seem apparent. He has indicated his charging voltage is 14.2 volts. Quite normal.

It should be understood that the alternator does not regulate the output voltage ex post facto. It regulates the stator output voltage by varying the rotor field voltage based upon what it "senses" at a given load point. If the sensed voltage goes up to high, then the regulator decreases the field voltage, and vice versa for a drop in sensed voltage.

Overcharging of the battery is due to an overvoltage condition at the battery and not alternator output current.

Again to quote:

"Extended periods with higher than 14.2volt level will over-charge the battery"

 

[67HEAVEN]

:Silly

Voltage ain't the problemo. As noted above, it's a constant 14.2 while running.

However, the in-dash ammeter (and my multimeter) both indicate a constant +40 amperes situation.

So, let's put KOPBET's Ohm's Law to use.

V = I × R
V = voltage in volts (V)
I = current in amps (A)
R = resistance in ohms (

)


In a "normal" driving scenario for a midyear:
V = I X R
14.2 volts = 2(? guesswork) amps X 7.1 ohms

My driving scenario:
V = I X R
14.2 volts = 40 amps x 0.355 ohms

What has this taught me? Too many amps..............not enough ohms (resistance).

I know.

Disconnect the Ammeter (the in-dash gauge marked Battery) and fergetaboutit.

 

[bossvette]

:Silly

Voltage ain't the problemo. As noted above, it's a constant 14.2 while running.

However, the in-dash ammeter (and my multimeter) both indicate a constant +40 amperes situation.

So, let's put KOPBET's Ohm's Law to use.

V = I × R
V = voltage in volts (V)
I = current in amps (A)
R = resistance in ohms (

)


In a "normal" driving scenario for a midyear:
V = I X R
14.2 volts = 2(? guesswork) amps X 7.1 ohms

My driving scenario:
V = I X R
14.2 volts = 40 amps x 0.355 ohms

What has this taught me? Too many amps..............not enough ohms (resistance).

I know.

Disconnect the Ammeter (the in-dash gauge marked Battery)
and fergetaboutit.

I prefer Voltmeters myself and actually have one in my 76 its not a perfect match but then I don't enter in NCRS shows; the funny part is no one has even noticed its there instead of the origional. I just replaced the origional with a Voltmeter I had laying around.

 

[SPANISHVETTS]

If the Alternator is putting out 14.2 volts there is no way that you are charging 40 Amps. Your problem is more than likely in the wiring. The Amp meter may be indicating the total current flow or at least the flow through some circuits instead of the charging current.

With the voltmeter connected to the battery positive and ground compare the voltage with every thing turned off and then with every thing turned on. After a few seconds the two readings should be close to equal.

Any modern lead-acid 12 volt car battery will handle a 14.7 volt charge indefinitely so you should not cook the battery at 14.2 volts. I regularly charge batteries at 15.5 volts and have not experienced any premature failures.

 

[KOPBET]

What has this taught me? Too many amps..............not enough ohms (resistance).

Ohm my God...

Actually, it depends on where you are measuring the amps . In your case it doesn't seem unreasonable to me considering where you are measuring the current. If you really want to know, why not put a clamp on ammeter on the + battery cable and check it? Wasn't the intent of the ammeter (where positioned) to indicate charging (into +) or discharging (out -) current of the battery? Current in or + meant a charging battery and current out of or - meant a discharging battery. Therefore the position of the ammeter should be in correspondence with the charging current and not the load.

Regardless, if the voltage at the battery is 14.2 volts then you aint gonna kill it. :W

I know.

Disconnect the Ammeter (the in-dash gauge marked Battery) and fergetaboutit.

Great idea! :L Better yet, send it to me! (the car too, not just the ammeter)

 

[KOPBET]

If the Alternator is putting out 14.2 volts there is no way that you are charging 40 Amps. Your problem is more than likely in the wiring. The Amp meter may be indicating the total current flow or at least the flow through some circuits instead of the charging current.

 

 

[67HEAVEN]

 

[67HEAVEN]

Your problem is more than likely in the wiring.

Every wiring harness in the car is brand new from Lectric Limited.

With the voltmeter connected to the battery positive and ground compare the voltage with every thing turned off and then with every thing turned on. After a few seconds the two readings should be close to equal.

Check. It is.

:confused

The Chevy dealer, where I bought the updated alternator, thinks the internal regulator is the problem. They didn't bother to test it....just ordered a replacement for me to exchange on Tuesday.

 

[magicv8]

67heaven - don't get carried away - that's not an ammeter

The gauge reards BATTERY. It actually is a galvanometer reading the voltage difference between the starter and the horn relay.

Get a voltmeter or a real ammeter.

If you want to protect the battery meter, put a 1 or 2 amp fuse on one of the wires to the gauge and ignore it.

Check the details page linked off my homepage (listed below) to see how to connect the fan from the alternator - so it doesn't effect your BATTERY gauge.

 

[67HEAVEN]

It actually is a galvanometer reading the voltage difference between the starter and the horn relay.

MagicV8,

Is the gauge telling me there is a 40 volt difference between the starter and the horn relay?????? :confused

 

[KOPBET]

The gauge reards BATTERY. It actually is a galvanometer reading the voltage difference between the starter and the horn relay.

And it even measures "negative" voltage!

door open (courtesy lights on) -05 reading
add parking/tail lights -15 reading
add low beam headlights -20 reading

 

[Billybeau1]

Man you guys wore this to death over the weekend. I'ts only Monday morning and now my head hurts

We'll find out on Tuesday right?