How to tell if alt. has internal volt reg?

[Gary Spaid]

I haven't gotten to check those things suggested but I can add a bit to the picture. I already rerouted the key 'on' wire and the start wire directly, thus bypassing the bulkhead connector. I think he got the 100 amp alternator because of electric fans.

 

[70bigblockdodge]

I haven't gotten to check those things suggested but I can add a bit to the picture. I already rerouted the key 'on' wire and the start wire directly, thus bypassing the bulkhead connector. I think he got the 100 amp alternator because of electric fans.

The upgrade is okay with high demands of modern things, fans, A/C, electronics. I just get weary of other people's skills with a direct current system, my paranoia.

 

[Gary Spaid]

OK maybe a better picture. The blue wire at top is not connected to alternator...is a ground to the block. What I thought were two green wires are one green and a blue wire near stud for the battery. So I have a green a blue and a black wire. I have verified the green goes to ground as I thought at the bracket. I am trying to trace blue wire but it may have to wait til tomorrow. It appears to connect to run wire at br.

 

[Gary Spaid]

Correction thanks to spell check. The green wire is grounded at the br (not bracket).

 

[70bigblockdodge]

I don't think you need any of that connected except the big black wires(one wire alternator) I think someone just ran those wires somewhere because they bought a replacement harness and those would be field wires. Just my guess.

 

[Gary Spaid]

I will try that tomorrow. Cross your fingers. Thanks!

 

[RemCharger]

I don't think you need any of that connected except the big black wires(one wire alternator) I think someone just ran those wires somewhere because they bought a replacement harness and those would be field wires. Just my guess.

Interesting. So how would the field get energized to generate power.

 

[Gary Spaid]

Interesting. So how would the field get energized to generate power.

According to March it is self activating.

 

[Gary Spaid]

I will try that tomorrow. Cross your fingers. Thanks!

OK, I have removed both the green wire and the blue wire. Car still starts and runs. Ammeter looked much better. I will let this sit for a few hours to see if there is still a battery drain.

 

[72RoadrunnerGTX]

It would appear the March alternators are in fact Tuff Stuff products. Their “one-wire” Chrysler alternators are not actually internally regulated, has a small regulator is attached externally to the “square-back” alternator case and uses one field terminal grounded through its mounting screw.

As mentioned, the pictures posted show a dual isolated field externally regulated version of that alternator, will require a later electronic external regulator to operate as designed. Pictures and wiring description appear to show it is wired without a regulator and is likely running in a constant state of “full field” with one terminal grounded and the other connected to ignition1(blue wire). Don’t see where a measured output voltage has been posted to verify.

 

[Gary Spaid]

It would appear the March alternators are in fact Tuff Stuff products. Their “one-wire” Chrysler alternators are not actually internally regulated, has a small regulator is attached externally to the “square-back” alternator case and uses one field terminal grounded through its mounting screw.

As mentioned, the pictures posted show a dual isolated field externally regulated version of that alternator, will require a later electronic external regulator to operate as designed. Pictures and wiring description appear to show it is wired without a regulator and is likely running in a constant state of “full field” with one terminal grounded and the other connected to ignition1(blue wire). Don’t see where a measured output voltage has been posted to verify.
View attachment 1530280

As I noted this morning it now is NOT connected green to ground and blue to ignition. It was that way in the pictures. Are you saying that I should reconnect them? Before I do that I will fire her up and check voltage at battery. Now before firing and sitting for about 3 hours I have about 12.7 V.

 

[Gary Spaid]

As I noted this morning it now is NOT connected green to ground and blue to ignition. It was that way in the pictures. Are you saying that I should reconnect them? Before I do that I will fire her up and check voltage at battery. Now before firing and sitting for about 3 hours I have about 12.7 V.

OK I just fired it up. Voltage dropped a bit to 12.3. Ammeter shows discharging when running. I don't think I am getting anything from the alternator wired as it is.

 

[eldubb440]

back in the day, we used to pull the positive terminal........ if it stays running, it's charging

I'm sure someone will say it's a bad idea, but I never seen it hurt anything on an old car........... not saying do it, just tripping down memory lane

 

[Gary Spaid]

OK I just fired it up. Voltage dropped a bit to 12.3. Ammeter shows discharging when running. I don't think I am getting anything from the alternator wired as it is.

I took another picture and do not see the vr as in your picture. Does anyone see a vr here?

 

[Gary Spaid]

View attachment 1530325
I took another picture and do not see the vr as in your picture. Does anyone see a vr here?

OK, if there is no vr then I need to get one, right? To install one I take it I will need that green alt wire (ground) and the blue alt wire (ignition) hooked to the vr. Would that be correct?

 

[72RoadrunnerGTX]

OK I just fired it up. Voltage dropped a bit to 12.3. Ammeter shows discharging when running. I don't think I am getting anything from the alternator wired as it is.

Then re-connect the field leads as it was, measure again. If it over charges, the alternator is not being regulated, as it would appear from the pictured wiring configuration. If you have a current draw while at rest, may not have anything to do with this field control wiring. Need to measure the current draw as the first step to diagnose the cause.
Disconnecting the battery on a running engine creates a very risk of over-volt damage to various electrical components. Many other more safe ways to troubleshoot the charging system.

For the ’70 and up electronic vr that alternator requires, the green wire is wired directly to the vr, its not a ground. The ign1 remains at the other field terminal as well as at the vr.

 

[Gary Spaid]

Then re-connect the field leads as it was, measure again. If it over charges, the alternator is not being regulated, as it would appear from the pictured wiring configuration. If you have a current draw while at rest, may not have anything to do with this field control wiring. Need to measure the current draw as the first step to diagnose the cause.
Disconnecting the battery on a running engine creates a very risk of over-volt damage to various electrical components. Many other more safe ways to troubleshoot the charging system.

No battery voltage drop when sitting. I will reconnect both blue and green, then check voltage at battery. May not do this til later...too hot now. Thanks everyone for helping out.

 

[Gary Spaid]

No battery voltage drop when sitting. I will reconnect both blue and green, then check voltage at battery. May not do this til later...too hot now. Thanks everyone for helping out.

Based on that illustration I need to get an electronic vr and a dual br. I think the green wire going to ground is causing the voltage drop and discharge while running. I am not running it again til I can get those changes made.

 

[72RoadrunnerGTX]

Based on that illustration I need to get an electronic vr and a dual br. I think the green wire going to ground is causing the voltage drop and discharge while running. I am not running it again til I can get those changes made.

The ballast resistor has nothing to do with the charging system. The ECU determines what BR is used, 4-pin vs. 5-pin. No reason to change it.

 

[Gary Spaid]

The ballast resistor has nothing to do with the charging system. The ECU determines what BR is used, 4-pin vs. 5-pin. No reason to change it.

I have the Chrysler ecu P4120505. I believe it is 4-pin.