Hi all,

Test #1 results= 15.60 volts from alternator to ground, 15.60 volts from battery to ground. 0 volts different.

Test#2 Results= 15.17 volts (engine was warming up).

Test #3 Results= 15.00 volts ( engine was warmed up. Got this with both fast and regular idle).

From what I am seeing, I think it changed a little bit, due to the motor warming up, but it still seemed(felt?) like it was getting more juice. It is consistently staying at 15 volts or higher.

Still too high. Very strange! Let's see what happens with CS' adjustable-regulator experiment.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I have a bazillion resistors here. Charrlie, do you have any guesses as to what resistance your small light bulb is? I can try the resistor trick, and see if that gets close.

Thanks,

G

I didn't measure the resistance. It was 3157 bulb, tail/stop. just clipped on a couple of leads to one filament.
I had tried a variable resistor, I use to simulate sensors, but it couldn't handle the current, and it lost all its "magic smoke"

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

The 3157 bulb has two filaments: the "major" (bright) one rated 26.9 watts at 12.8 volts, and the "minor" (dim) one rated 8.26 watts at 14.0 volts. These are nominal ratings; production values are nowhere near as precise as with calibrated resistors. Nevertheless, let's go with those values. "Twinkle, twinkle, little star; power equals I-squared R":

Major filament

26.9 = [(2.1)(2.1)]R

26.9 = 4.41R

R = 6.1Ω

Minor filament

8.26 = [(0.59)(0.59)]R

8.26 = 0.3481R

R = 23.7Ω

Of course, using a bulb as a resistor is a handy test, but not a good fix; as soon as the bulb burns out, you lose all charging.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks for the physics refresher, Dan. I am wondering how many amps it took to burn out the Variable resistor that Charrlie was using? I didn't think that the field wire current would be very high.

[EDIT] In reading back and checking, would the field connection really draw 7 amps? That seems pretty high. [/EDIT]

I will start digging around in my box o' resistors, and see what I have.

Thanks again!

G

If I remember correctly the current was over 2, but less then 4 amps. The resister was similar to a volumm control. No current handling capacity.

The field draw, would depend on the design of the alt. It is possible the altnator for use with the adj regulator is for a commercial truck or police/fire vehicle, and has a different internal design. When I was building fire trucks, the alternators all were 200 amps minimum, with adj regulators. Part of the preship inspection/setup was to full load the electrical system, and adj the regulator for 13.8 to 14.2 volts.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Next experiment- Resistors in the field circuit

I put a 10 Ohm (10 Watt) power resistor in the circuit.

Cold engine
Voltage at 13.3 Volts.

I might wire this up on a board, and go with this for now. That is pretty close. If I could find a 7 Ohm power resistor, I would try that, and see if I could sneak up on 14 volts.

13.3 is lower than you want. Keep in mind that the charging voltage temperature compensation depends on ambient temperature, not engine temperature, as a proxy for battery temperature, which is what really matters. As the engine gets warm it'll heat up the engine compartment and battery. You should shoot for the following (temperature right at the voltage regulator, but not touching it):

0° to 50° F: 14.45 to 14.95V
50° to 100°F: 13.85 to 14.45V
100°F to 150°F: 13.75 to 13.85V
150°F to 200°F: 13.75V

Once you get your resistor selection roughed-in to get you into the right ballpark, try heating the regulator with a hair dryer while you watch the voltage across the battery on your voltmeter, to make sure you have roughly this kind of temperature/voltage curve.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Agreed, 10 ohms is too much. I am getting 12.6 volts warmed up. I gotta find a 5 ohm power resistor around here.....

G

What happens to the voltage when you put a load on the system (lights, fans,etc.) ?

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Just called to check on my adj VR. It was back ordered, but Weitzels should have it in a couple of days. It will then be shipped to me. I should have it within a week.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Hi all,

I got back to the project today. After trying the hair dryer trick, and a bunch of different resistors, I am back to square one.

Well warmed up, without a resistor, and after hair dryering the VR, I am getting 13.79 volts out of the alternator.

I need to keep monitoring this, obviously.....

I'm kinda curious to know if you've tried more than just the one regulator, GMader.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

2nd test, after a good test drive, and well warmed up.

13.3 V, without any resistors.
Same Voltage Regulator, no changes there.

I am using the same multimeter, in the same way.

I did go through all the connections completely. Maybe I inadvertently fixed a bad connection, or ground.

I give.