another not charging thread

[Bigredlid]

i have been reading some of the older and other threads about this topic. None of them are the exact scenario. so here goes.

I recently had the engine out of a 67 Belvedere . it took a lot longer in the engine shop and by the time I put it back in the wiring was not in recent memory.

anyway after getting it back on the road eventually I had a dead battery. the battery was brand new.
battery has been tested as ok by my brother who works at the part store

it wasn't charging so I bought a new alternator. which didn't fix the problem
-first question the second field I have grounded to the body of the alternator, is this correct?. car has the old style voltage regulator.

I replaced the voltage regulator also which did not fix the problem.

facts to know
-switch on there is juice at the regulator, off- none
-its reading voltage nearly same at battery and alternator field one, where the green wire is connected.

It has a oil pressure switch that is wired to the system. I could not remember the wires it has three. it would not start and I had to switch the wires around to get it to start

 

[67Dart273]

Just for "because" what is the car that it is installed into? What year/ model?

The older style, that is, 69/ earlier is a simple circuit. The ignition "run" wire branches off to feed the VR which MUST be grounded. The field wire of the VR (green) goes to the alternator.

The alternator output (the big wire, stud, BLACK) goes through the bulkhead to the ammeter circuit, back out the bulkhead on big RED, through the fuse link, and to the starter relay stud (junction point) and to the battery

So for starters get the battery recharged, run the engine on fast idle to simulate low to medium cruise speed/ RPM

Measure battery voltage and then voltage at the output stud of the alternator. They will both be likely low, below 13.5V

If the alternator is very high, say, 15 or more, and the battery is low, this means there is a break or bad connection in the output wire

If the alternator is low, below 13, then it is not charging

Now "rig" a jumper wire. Remove the green wire from the alternator field, and jumper from the alternator terminal to the battery. With the engine running, it should bog down a bit, you should hear the alterator whine, and the output voltage should go up.

If not, recheck the voltage at the output stud. If the voltage is still low, below 13 with your jumper connected the alternator is not charging.

First thing to do is check the brushes for wear, stuck, grease, dirt, etc. If they seem OK you likely should just replace the alternator.

I would NOT buy another early one unless you are looking to be "restore correct." Get a 73/ later and make sure it has the squarish heat sink. "Square back" rather than "round back" like you have now. All you need to do with the newer one is to ground one of the 2 field connectors, then connect as your old one.
=====================================================

Now, in the above tests, if your jumper wire DID CAUSE the alternator to charge, you now have a problem in the field/ VR circuit. Either the green wire is broken, the VR is ungrounded, the VR is bad, or the VR is not getting ignition "run" power to the VR

Checking for power is easy, simply use a multimeter at the IGN terminal of the VR. Make absolutely certain the VR is grounded. The green wire only goes one place---from the VR FLD connection to the alternator field. Easy to check.

It is certainly possible the new VR is defective (out of the box), or that the alternator field is shorted, and blew up the new VR.

 

[67Dart273]

By the way if you end up buying an alternator and do get a newer style, you can add just one more wire and convert the system to the 70/ later VR.

 

[Bigredlid]

I already replaced the alternator with a square back and grounded the second (lower) field to the body of the alternator case. The car is a 67 Belvedere. low deck stroker. still has the factory wiring.

The green wire only goes one place---from the VR FLD connection to the alternator field. Easy to check

so should I just run a wire from the top field of the alternator to the VR? to see if the wire is bad

 

[67Dart273]

That is one way. Much easier faster just to disconnect it at both ends (takes about 30 seconds) and check continuity through the wire, and from the wire to ground.

 

[KP]

Need help wiring my charging system.

Thank You

 

[Tylan]

Just for "because" what is the car that it is installed into? What year/ model?

The older style, that is, 69/ earlier is a simple circuit. The ignition "run" wire branches off to feed the VR which MUST be grounded. The field wire of the VR (green) goes to the alternator.

The alternator output (the big wire, stud, BLACK) goes through the bulkhead to the ammeter circuit, back out the bulkhead on big RED, through the fuse link, and to the starter relay stud (junction point) and to the battery

So for starters get the battery recharged, run the engine on fast idle to simulate low to medium cruise speed/ RPM

Measure battery voltage and then voltage at the output stud of the alternator. They will both be likely low, below 13.5V

If the alternator is very high, say, 15 or more, and the battery is low, this means there is a break or bad connection in the output wire

If the alternator is low, below 13, then it is not charging

Now "rig" a jumper wire. Remove the green wire from the alternator field, and jumper from the alternator terminal to the battery. With the engine running, it should bog down a bit, you should hear the alterator whine, and the output voltage should go up.

If not, recheck the voltage at the output stud. If the voltage is still low, below 13 with your jumper connected the alternator is not charging.

First thing to do is check the brushes for wear, stuck, grease, dirt, etc. If they seem OK you likely should just replace the alternator.

I would NOT buy another early one unless you are looking to be "restore correct." Get a 73/ later and make sure it has the squarish heat sink. "Square back" rather than "round back" like you have now. All you need to do with the newer one is to ground one of the 2 field connectors, then connect as your old one.
=====================================================

Now, in the above tests, if your jumper wire DID CAUSE the alternator to charge, you now have a problem in the field/ VR circuit. Either the green wire is broken, the VR is ungrounded, the VR is bad, or the VR is not getting ignition "run" power to the VR

Checking for power is easy, simply use a multimeter at the IGN terminal of the VR. Make absolutely certain the VR is grounded. The green wire only goes one place---from the VR FLD connection to the alternator field. Easy to check.

It is certainly possible the new VR is defective (out of the box), or that the alternator field is shorted, and blew up the new VR.

What is the purpose of the two fields? Does it matter which wire is connected to which field connection on the alternator? I'm having a similar issue to big red with my 74 Duster (square back alternator) , no charge at the battery with a fairly new alternator. Even got it tested by an auto parts store recently and they said it was "doing it's job." From the testing I've done, I've used a multimeter putting the positive probe on the main post of the alternator and negative Probe on a ground, reads ~12.5 volts when running. I also replaced the VR, which helped nothing. So I'm stuck with the problem either being the alternator is actually bad, despite the test, or there is some bs wiring mishap somewhere obscure. I wouldn't be surprised by the latter, the wiring in this car has seen better days.

 

[Phreakish]

What is the purpose of the two fields? Does it matter which wire is connected to which field connection on the alternator? I'm having a similar issue to big red with my 74 Duster (square back alternator) , no charge at the battery with a fairly new alternator. Even got it tested by an auto parts store recently and they said it was "doing it's job." From the testing I've done, I've used a multimeter putting the positive probe on the main post of the alternator and negative Probe on a ground, reads ~12.5 volts when running. I also replaced the VR, which helped nothing. So I'm stuck with the problem either being the alternator is actually bad, despite the test, or there is some bs wiring mishap somewhere obscure. I wouldn't be surprised by the latter, the wiring in this car has seen better days.

The two wires can go on in either location, doesn't matter.

Check that the regulator is grounded to the firewall and there's some checks you can do to the regulator too. Search Google or YouTube for "Chrysler voltage regulator check" which will give you some good info.

 

[Mattax]

What is the purpose of the two fields?

See this post Identifying Chrysler Alternators (1960-1976)
and then scroll up in the thread to see photos of the parts.

I've used a multimeter putting the positive probe on the main post of the alternator and negative Probe on a ground, reads ~12.5 volts when running.

That means the engine is running on battery power. The ammeter should be showing discharge.

Then the question to answer is whether the field is getting power. (see the link above for explanation).
Begin answering this question by measuring the voltage at the field terminal with the blue wire. You'll have to backprobe.
> Voltage here should be the same as the rest of the system.
IF it is, then place a jumper wire from the other field terminal to a ground with the engine running at slow idle.
Make a quick check of the system voltage and the ammeter (battery charging).

Do not run the engine at high rpm and do not keep it running it if the ammeter is showing high rate of battery charging.

 

[Tylan]

See this post Identifying Chrysler Alternators (1960-1976)
and then scroll up in the thread to see photos of the parts.


That means the engine is running on battery power. The ammeter should be showing discharge.

Then the question to answer is whether the field is getting power. (see the link above for explanation).
Begin answering this question by measuring the voltage at the field terminal with the blue wire. You'll have to backprobe.
> Voltage here should be the same as the rest of the system.
IF it is, then place a jumper wire from the other field terminal to a ground with the engine running at slow idle.
Make a quick check of the system voltage and the ammeter (battery charging).

Do not run the engine at high rpm and do not keep it running it if the ammeter is showing high rate of battery charging.

I can confirm the blue field wire is getting voltage, albeit around a volt less than the battery itself, not sure if that is important. So, I jumped a wire from the other FLD terminal directly to the negative battery post, started the engine up and low and behold, still no charge... (Reads ~12.5v)

However, I found it interesting that after removing the negative clamp from the battery with the jumper wire still attached to the post, the engine continued to run, so there is charge going somewhere...
Edit: I just realized my previous observation probably just means it's still running off the battery.

 

[67Dart273]

I found it interesting that after removing the negative clamp from the battery with the jumper wire still attached to the post, the engine continued to run, .

DO NOT DO THIS. Learn to troubleshoot using proper test equipment, even a test light can be helpful

HOW IT WORKS

You have two major circuits here, and two major componentsl

1....The main charge output and "path" of that circuit goes from the alternator output stud to the battery +

2....The field circuit which mostly is batter--fuse link--bulkhead connector---igntion switch and connector--back out through bulkhead (ign1 or ignition run) to VR ign terminal--through VR---to one field terminal on GREEN---through alternator field----to IGN1 through light BLUE wire

3....The alternator "and is it bad"

4...The VR and is it grounded and is it bad?

WHAT YOU NEED. Some alligator clip jumper wires, a 12V test lamp, and a multimeter

HOW TO TEST

There are several ways

1....In a no -charge condition, you want to get field current into the alternator to make it charge, see if it has output, then find out why or why not.

Remove GREEN field wire, turn key to "run" and jumper the disconnected field terminal to ground. In quiet, and subdued light, you should see and hear a small spark. Connect the jumper and measure the opposite field terminal. Should be about the same as battery.

Start engine, slowly bring up RPM with meter connected to BATTERY. Battery voltage should rise, depending on how far "down" the charge is. Try not to let voltage go above 16V

If the battery V does NOT rise, switch your meter over to the alternator output stud (and ground) Repeat the test. If the voltage does not rise at the alternator stud, either the field circuit is not drawing current, or the alternator is bad. Bad field windings, bad stator, bad diodes, etc or bad brushes/ brush connections---OR THE WIRING you have connected is not actually supplying field power/ voltage

To double check the field is drawing current, shut off engine, turn key back to "run." Disconnect field jumper to ground. Set your multimeter up for current (highest amperage scale 10A or 20A) Hook meter in series from disconnected field terminal to ground. you should measure several amps, at least 3 or more. If so, the field is drawing some current, and if it won't charge, the trouble is in the alternator stator/ diodes

 

[Mattax]

You timed that well. I just stopped by the computer...

I can confirm the blue field wire is getting voltage, albeit around a volt less than the battery itself, not sure if that is important.

Yes. It means current is flowing through resistance. How much discharge was the ammeter showing?

So, I jumped a wire from the other FLD terminal directly to the negative battery post,

OK. Good to know. Easier to use the engine block or a bracket on the block or heads but what you did should have ensured current flow through the rotor amd back to the battery.

(Reads ~12.5v)

At the alternator output terminal or the battery?

However, I found it interesting that after removing the negative clamp from the battery with the jumper wire still attached to the post, the engine continued to run, so there is charge going somewhere...
Edit: I just realized my previous observation probably just means it's still running off the battery.

When 67Dart273 sees this he's going to yell at you.... not to do that!
edit. Beat me to it!

However since you have done it. It does not mean the engine is running off battery. You were correct in your first thought. When there is no ground connection to battery, the battery can not provide power.
For current to flow it needs a complete circuit.

 

[Tylan]

Yes. It means current is flowing through resistance. How much discharge was the ammeter showing?

Well, the ammeter on this car is long gone, it was in pieces by the time I got the car and the previous owner spliced the two wires together. I'll have to follow the circuit at some point and look for any corrosion.

At the alternator output terminal or the battery?

Both locations show under 13v, though I think I saw over half a volt more when probing the alternator output.

When 67Dart273 sees this he's going to yell at you.... not to do that!
edit. Beat me to it!

However since you have done it. It does not mean the engine is running off battery. You were correct in your first thought. When there is no ground connection to battery, the battery can not provide power.
For current to flow it needs a complete circuit.

Noted! I'm a little confused though. I had put both the negative clamp AND the jumper wire on the negative post, just to clarify, and then I took off the negative clamp WITH the jumper wire still on the post and engine kept running. As soon as I removed the wire the engine stopped. Doesn't this mean it was taking power from the battery? (I won't do it again 67Dart273)

 

[Mattax]

edit

I had put both the negative clamp AND the jumper wire on the negative post, just to clarify, and then I took off the negative clamp WITH the jumper wire still on the post and engine kept running.

Ok. That makes sense

For current to flow it needs a complete circuit.

The power circuit looks like this:

If the system was being powered the battery, the current flows from the battery positive to the negative.
The current path to the ignition is marked with orange arrows. The ECU, coil and spark plugs all connect to ground. Ground connects to the battery negative post.

The amount of flow is called current.
The ammeter should show a couple of amps flowing out of the battery to power the ignition.
The voltage of the current should still be 12.5 Volts when it gets to the ballast resistor.
Any loss of voltage indicates resistance in the path of the current.

The same goes when the alternator is supplying power. Even if its running poorly.
The circle is completed like this.

 

[67Dart273]

Doesn't this mean it was taking power from the battery? (I won't do it again 67Dart273)

I may have misunderstood your connections. What I was getting at is the old "wives tale test" It goes like this:

You start the car and run it and while running, you pull one cable off the battery. The "supposed" answers are that if the engine stops, the alternator is bad

WHY this is not only a bad idea, but WHY it does not prove much

First, with more and more electronics in cars, a voltage spike caused by a WORKING alternator can damage electronics

Second, the "test" does not prove anything, why:

1..."Let's say" the car happens to be running quite slow, and the battery somewhat down, and you happen to have "maybe" left something like the heater blower on low. "It might just be" that when you pull the cable off, a WORKING alternator might not be able to put out enough at low RPM to keep things going, and you might wrongly conclude the thing is bad

2...The OPPOSITE worng conclusion can come into play: Let's say you have no loads powered in the car, so minimal draw. Let's say you have the engine idling fairly fast RPM. Let's say the alternator actually has a BIG problem, like 4 of the 6 diodes are blown open. So the alternator is not putting out "much." You pull the cable, and it keeps right on running!!! So you "think" the alternator is good!!! When, in fact, it is barely able to provide basic ignition power, (and in addition delivers an incredibly dirty output wave)

 

[Mattax]

Well, the ammeter on this car is long gone, it was in pieces by the time I got the car and the previous owner spliced the two wires together.

OK. Since you have a voltmeter you can still do a lot of diagnoses.
We'll have to assume the currents, and you can make some additional voltage drop comparisons.
Ignition: 2-4 amps
Rotor (alternator field): 2.5-5 amps
Brake lights: 2.5 amps
Parking lights: 4 amps
Headlights plus parking lights: 13 amps
Battery charging: 0 to 50 amps or more depending on how discharged it is.

Both locations show under 13v, though I think I saw over half a volt more when probing the alternator output.

Increasing current through a point of resistance will cause a larger voltage drop.
Conversely, when there is relatively low current flow, as is the case with just the engine running, there should be no measureable voltage drop.

My suggestions, if 67dart273 hasn't already made them, is to measure voltage differences in the circuit. This will remove the question of whether the ground circuit has resistance - in which case ground is not a good reference.

 

[Mattax]

Here's an example:
Lets say at the alternator positive post is 13.5 Volts and the the voltage at the battery positive is 13.0Volts.
Now measure the voltage between the alternator positve and the battery positive.

Since the difference is 0.5 Volts Now we can expect the problem is in the positive wiring not the ground wiring.

Lets take this example further.
Lets say the battery is very low, and the most power the alternator can produce at idle speed is 460 Watts
In that case what might be happening is the alternator is struggling to provide the battery all of what it wants.

So instead of providing power at 14 Volts, the alternator struggles and proivides power at a little lower voltage. This reduces demand a little. Result is alternator output of 34 amps at 13.5 Volts (which is 459 Watts)

Resistance to that 34 amps through the R6 wire, especially at the firewall, and resistances to the 30 amps flowing from the main splice to the battery show up as a voltage drop.

 

[Mattax]

Here's a way to narrow down points of resistance using voltage drops.

Turn the key to accessory, turn on the heater fan.
Measure if that causes voltage drop the battery positve and the main splice.
Even without the ammeter, we know the fan pulls a fair amount of current, especially in high.

Or you can do the same test with the key off. Turn on the parking lights, and then the headlights.

 

[Tylan]

Ok guys, I've done a little fiddling with the wires the past few days and have come to this hypothesis: the alternator field is not getting enough power because of a voltage drop somewhere in the cabin, showing almost a volt drop at the field terminal.
The ignition switch is getting full power from the battery and is sending it through with little resistance. When I see the drop is when the key is in the run position with a little under 1/2 volt drop, even though nothing is on. No motors, no lights, nothing. (Is this from the ignition parts and is normal?) This drop is more exaggerated when I probe the blue ignition wire splice, which seems to be more affected, around 0.1-0.2 difference. Something worth noting, when I unplug the harness for the climate controls, the drop is lessened by about 0.2 volts. This is the only thing that seems to affect the drop since unplugging the wiper motor doesn't affect it, and the radio is removed.
Also, just to clear it up, the output terminal of the alternator field should be less voltage than input terminal right?

 

[67Dart273]

ALL these old girls will have SOME drop. A couple -4 tenths is not going to cause a reduced charge condition (to the VR/ field circuit) it is going to rather cause OVER voltage, OVER charge. This is because the VR keeps ramping up the field to keep the VR IGN terminal at the VR setpoint, which should be about 14. When that happens, the battery will run ABOVE that voltage by the amount of the TOTAL drop from battery neg to VR case, and from battery POS all the way through the harness and to the VR IGN terminal.

MAYBE the alternator is not putting out it's rated power and MAYBE it's either a too small unit or has an electrical problem

"The way to tell" ultimately is to make up a pair of say, no14 wires long enough to jumper straight battery power direct to the two field terminals. With the battery up and all loads on, a slow rise in RPM should easily raise the battery voltage to 16+ and I would not allow it past that. IF YOU HAVE a battery load tester (carbon pile) you can dial in load amps and see just what it will keep up with. In other words, dial in say, 50A on the load tester, raise engine RPM with field wired direct, and the battery should sit no less than "about" 13V or more.

 

[Tylan]

"The way to tell" ultimately is to make up a pair of say, no14 wires long enough to jumper straight battery power direct to the two field terminals.

After doing this I still had no luck. I also used the warranty and got the alternator replaced, still no luck even after doing the same field jump test.

At this point I'm contemplating just doing a full overhaul of the charching circuit.

 

[Mattax]

Also, just to clear it up, the output terminal of the alternator field should be less voltage than input terminal right?

Yes IF;
If you're talking about just the field terminals.
and
current is flowing.

The power used to create the magnetic field comes from current flowing through the rotor windings. The electricity loses power in the process.
Think of a light bulb. Voltage on the input is high, on the output side is low. usually its zero Volts. But if there is a dimmer (resistor) on the output side it will be above zero but less than input.

When I see the drop is when the key is in the run position with a little under 1/2 volt drop, even though nothing is on.

No motors, no lights, nothing. (Is this from the ignition parts and is normal?)

See post #14. But I think you answered your own question. ;)

This drop is more exaggerated when I probe the blue ignition wire splice, which seems to be more affected, around 0.1-0.2 difference.

What I call a splice should be welded. Really don't know what you probed or the conditions or the reference (what the otehr probe is clipped to)

Something worth noting, when I unplug the harness for the climate controls, the drop is lessened by about 0.2 volts.

Climate controls ? Which harness connector?
Whatever you disconnected must have some current through it going somewhere.

I'd start with the tests outlined in post #14

Then charge the battery
After its charged, start the car and do the same tests with the probes reversed.
Test immediately, and then after a few minutes.

Then you'll know if there is resistance in either or both feed to the main splice.

Only after that would I move on to exploring resistance in the switch, or ignition, and field circuits.

 

[Tylan]

Climate controls ? Which harness connector?
Whatever you disconnected must have some current through it going somewhere.

The larger of the two harnesses on the back of the climate controls (heat, cool, defrost, etc.), not the harness that controls fan speed.

I'd start with the tests outlined in post #14

Then charge the battery
After its charged, start the car and do the same tests with the probes reversed.
Test immediately, and then after a few minutes.

Then you'll know if there is resistance in either or both feed to the main splice.

Only after that would I move on to exploring resistance in the switch, or ignition, and field circuits.

Alright, I'll get to that when I can.
Out of curiosity, do you guys have a preference in brand and condition of alternator? By condition I mean new vs re manufactured.