Not charging

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jwicker

jwicker

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Hello all - I recently got my 64 Dodge Dart with a nearly completely dead battery. I checked while running and the alternator was from 1983 and did not appear to be working. Voltage regulator was also very old.

I swapped the alternator (tested good) and voltage regulator and still can't get it to charge. The wiring is sure odd.....

The FLD terminal is going into a loom back towards the firewall, all the way across to the right, past the battery, back around front by the radiator and into the negative of the HORN. WTH??

The Positive or Charge cable - it goes into the same loom but I can't quite tell where it goes. It may stop at the ballast resistor or somewhere else.

I checked continuity to positive for the Charge cable - all good. FLD cable is continuous with Ground /Negative.

Any clue as to why it's not charging? The Chilton's book I have says that FLD should go straight to the regulator but I can't tell if that's what's happening already.
 
jwicker said:
Hello all - I recently got my 64 Dodge Dart with a nearly completely dead battery. I checked while running and the alternator was from 1983 and did not appear to be working. Voltage regulator was also very old.
Click to expand...
A '64 alternator has one field connection, an '83 alternator has two. to make the '84 alternator work, you must run a ground wire from the second (unused) terminal to a good solid ground. It doesn't matter which terminal is used and which one is grounded.
1688419639428.png

Just an FYI, the '64 has two fields also, but one was internally grounded, so no need for a ground wire on those.
 
jwicker said:
The FLD terminal is going into a loom back towards the firewall, all the way across to the right, past the battery, back around front by the radiator and into the negative of the HORN. WTH??
Click to expand...

There is no negative for the horn.
In fact there are hardly any negative wires.
While most grounds are black, black does NOT usually mean ground!
Many of the feeds are Black, especially in '64
 

See photos - newer shinier alternator has the exact same connections as the old. Only one FLD connection, one ground, and one BATT.

Any chance there's a fuse or something I don't know about?

IMG20230703144616.jpg


IMG20230703144611.jpg
 
jwicker said:
Any chance there's a fuse or something I don't know about?
Click to expand...
No.
In fact a '64 doesn't even have a fusible link.

The power supplies (battery and alternator) are wired to the main feeds and the ignition circuit as shown.
1688421680826.png


Safety Note:
As long as the battery positive is connected, everything joined at the welded splice (solid circle) is hot. Hit one of the connectors with a wedding band or wrench and the battery will do spark show and maybe some welding. Not fun.


jwicker said:
I checked continuity to positive for the Charge cable - all good. FLD cable is continuous with Ground /Negative.
Click to expand...
Read how alternators work in the "Identifying Chrysler Alternators" sticky.

jwicker said:
- newer shinier alternator has the exact same connections as the old. Only one FLD connection, one ground, and one BATT.
Click to expand...
They both look like grounded field alternators. The bottom one has been heavily sandblasted.
 
here's an animation of the current flow with the battery wanting a little recharging and the engine running at low rpm.

1688423246471.png


Because the alternator is turning slow, the regulator allows current to flow to the rotor near continuously.
After the battey is charged, demand will be low and the regulator will switch off and on through its resistors.

If wire R3 is grounded, or sees too high of a demand for any other reason, its internal fusible link will melt.
That's pretty much the only protection in the circuit.

And please. put that battery on a regulated charger.
 
Last edited:
jwicker said:
Only one FLD connection, one ground, and one BATT
Click to expand...
The green wire is not a ground.

It is the variable voltage feed from the voltage regulator.

The electro / mechanical voltage regulator takes battery voltage and varys it between roughly 5 to 10 volts to regulate the output voltage of the alternator.

In our cars black, green, and white are not usually grounds as someone already stated.
 
Dana67Dart said:
The electro / mechanical voltage regulator takes battery voltage and varys it between roughly 5 to 10 volts to regulate the output voltage of the alternator.
Click to expand...
Ever try to measure it?
I would think that on scope it would look like rapidly varying square waves. Above 1400 rpm with low demand going zero to a low voltage but no idea if its 5 or 10 V.
 
Mattax said:
Ever try to measure it?
Click to expand...
I had a voltage regulator that I thought was going bad so I measured it several times.

(Discovered it was a bad rotor, intermittent open)

Don't recall how I did it , ( I think I measured negative lead to ground, positive lead to field terminal?)

The higher the voltage the less it would be charging.

The lower the voltage the more it would be charging.

My particular single field wire VR has electronic guts from the 70s or 80s so it is constant output vs a square wave of sort.
 
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