electronic voltage regulator required with higher amp alt on my 68?

[grdprx]

What voltage did you see when you jumped the alt field to battery +?

Taking some time again to look into this problem I'm having.  I jumped the alt field to battery, got 14v.  So I'm guessing that means the alt is good.  Does this then mean the culprit is my regulator?

I think I did that already.

[68neverlate]

Been following this for a while and thought I'd pass along some info on my recent electrical issue... it may be of some help.      

I have a '68 that has the original round back (single field) alternator on it.  I had issues with my battery getting drawn down, so I had my alternator checked and it was only putting out 4.5 volts.  Replaced the alternator with a custom-built original (putting out 100 amps at max) and I started having pulsating issues with the power output (I still had a stock points style mechanical regulator).  By the way, I carried out wiring upgrades to handle the extra power of the new alternator before firing up the engine... a must if you're going to use a higher than stock output alternator!      

I took some power readings from my charging system to determine the source of the pulsating problem.  When I did that, I got about the same readings on the regulator that you're currently getting (12 - 14 volts on the ignition (blue) wire and about 2.5 volts (fluctuating) on the field (green) wire.  The charging system was all fine though other than the pulsating. 

My system was giving me more than enough power at idle, my issue was pulsating power.  It eventually ended up being the regulator... seems the old points style will work with the increased power, it just does a lousy job of keeping the voltage constant.  I replaced with an electronic regulator, and it solved everything.

All this to say that I don't think any of your readings around the regulator point to that being the issue (although you may want to replace with an electronic one for better performance).  Your voltage readings with just the battery connected (without the engine running) all seem reasonable (at alt, starter relay etc.) which suggests you currently do not have a bulkhead connection issue (although if you're running a square back 78 amp alternator I'd seriously suggest doing the wiring upgrades that Nacho has posted to the site here - the factory wiring was only designed to handle the output of a 46 amp max alternator).  Your readings all go to pot when you start the engine. 

My gut is telling me it's an alternator issue (the fact that you are not in a charge state at 1,500 rpms coupled with the voltage readings at the battery post of the alternator with the engine running point to that).

I'd try isolating (ungrounding) the field terminal that's currently grounded on the alternator and then check again for continuity between the fields and the case).  This time, if you have any continuity between either field and the case, you know you have an internal short in the alternator. 

My    for what it's worth my friend...       

[Charger RT]

here is the problem there is a voltage drop if the alternator and regulator were bad and the wiring good you should have voltage readings at the battery very close to when is read at the alternator stud. But the car does not. the voltage at the alternator is over 2 volts lower. Even the power feeding the regulator is over 2 volts lower then battery.

If the voltage was only low at the regulator I could think possible ignition switch. But the alternator stud is low.

If the bulkhead connector has an issue you should be able to see a problem with your eyes. take it apart and inspect it. I believe these 2 wires are the biggest gauge wires in the entire connector. Look for melted plastic around the connection and discolored terminals.

with the volt readings you got with it running you can't start diagnoising an alternator or regulator.
Tim

[68neverlate]

Yes, sorry Tim, I'm guilty of not playing close enough attention to the voltage readings when I posted... tried to squeeze it in between tasks here at work and forgot the readings. 

I agree that there could be a wiring issue at the bulkhead connector as there is a voltage drop of 0.8 volts from the battery to the stud on the alternator with the car off.  It is a fairly small drop though, so it may not be the only cause of the problems grdprx is experiencing.  The issue that stood out to me is the output at the alternator post when the car is running (9.5 - 9.6 volts)... from my understanding, 2.7 volts at the field should be more than enough for the alternator to produce 14+ volts at the output stud, regardless of what's going on after that (including a possible bad connection at the bulkhead).  Wouldn't you agree?     

Out here taking some measurements.  With the ignition off, the batt is at 12.2.  Same at starter relay and on the other end of the fuse able link at bulkhead.  Alt stud and black wire on bulkhead is 11.4.

With the car running, batt, starter relay, and fuseable link is 12.1.  Alt stud reads 9.5-9.6.  Blue wire on regulator is 9.3-9.5.  Green wire is 2.7 at regulator and field connector.

Is this pointing to a faulty regulator?  Or do I have a draw somewhere, because the alt is a volt short with everything off?

[elacruze]

any voltage drop of .5v or more is unacceptable, and in a circuit of that capacity (between altpost and battery) I would demand to see no more than .1v drop with engine off.

[Charger RT]

there may be an issue with the charging system but the voltage drop needs to be fixed first. grdprx has a .8 drop with the engine off that goes to around 2.5 volts engine running.

Fixing the voltage drop may fix the charging system.

Think of the amp meter as the middle of this circuit. battery power flow from battery to starter relay through the firewall to one of the amp meter studs. the wire on the alternator stud runs to the firewall goes through it and then to the other amp meter stud. Power inside the car comes off the alternator side of the amp meter. 

The regulator power is from a ignition circuit. Since its running voltage is the same 9.5 volt as the alternator stud. I would bet the fuse box reads that low as well. All the while the battery and starter relay is at 12.1 volt. plenty of voltage to move to the other side of the circuit to even voltage but it does not because of the drop.

So in my view the drop needs fixed before trying to get the charge volt to 14. Lets help grdprx get the alternator stud, regulator power in to what is on the starter relay before trying to get it to charge.

grdprx if this was my 68 i would check the bulkhead connector on the starter relay side first.
Tim

[grdprx]

Thank you very much gentlemen, I shall hunt down the voltage drop over the next few days, starting at the.  Bulkhead.  Bunch of useful leads.

[grdprx]

Well I feel sheepish...  I took a look at the bulkhead connector.  Bam!  That's the problem.  I do not remember it being in such bad shape, but alas, I shall get to work on fixing it.

I also cleaned the alternator with the electrical spray, it no longer has a circut to the case. 

Thanks again.

[Nacho-RT74]

tipical... and easy fix...

if interested, they are available NOS around... not cheap though, but I think not excesivelly expensive. Some ppl offers them with a full kit of male plugs and terminals

I think there are also repros available

[Charger RT]

Glad you found it.

while you are fixing that you might want to consider Nachos parallel circuit. It would take part of the load off your repair and help prevent it from happening again. One of the links I posted has info on it.
Tim

[Nacho-RT74]

http://www.ebay.com/itm/MOPAR-66-67-68-69-70-DODGE-PLY-BULKHEAD-CONNECTOR-NEW-REPRODUCTION-MARKET-/180764451919?pt=Vintage_Car_Truck_Parts_Accessories&vxp=mtr&hash=item2a1666a44f

[grdprx]

Glad you found it.

while you are fixing that you might want to consider Nachos parallel circuit. It would take part of the load off your repair and help prevent it from happening again. One of the links I posted has info on it.
Tim

Absolutely, that will be a part of the repair process.

Looking through some threads on the bulkhead connector, people are using a new style terminal connector from Napa.  Will that require replacing both male and female connectors?  I have a brand new engine harness, so I really don't want to do that...

[Nacho-RT74]

no need for that, and honestly with the repro bulkhead so cheap would simply replace the bulkhead assembly and clean and maybe polish all terminals to reinstall them. Plug and play.

there is a thread around to clean terminals on a vinegar and salt solution. Then clean the solution and use dielectric grease.

Is not a big job really.

then as Tim suggested, and I suggest too... run parallel wires to ammeter through the firewall and done. No need to remove the existant ones. The existant ones still in use will allow you to use 10 gauge for parallel instead 8 or bigger.

[68neverlate]

Well I feel sheepish...  I took a look at the bulkhead connector.  Bam!  That's the problem.  I do not remember it being in such bad shape, but alas, I shall get to work on fixing it.

I also cleaned the alternator with the electrical spray, it no longer has a circut to the case. 

Thanks again.

Wow, that connector has definitely seen some heat in it's day!   

Glad you were able to isolate the problems grdprx... it's definitely more difficult to pin down when more than one thing is happening at the same time.  Your plan to upgrade the wiring should keep you from having the bulkhead connector issue happen again... especially if you coat everything with dielectric grease on reassembling as Tim and Nacho suggested.  Interesting about dirt causing the internal short in the alternator... I'll be putting that one in the memory banks for future. 

Good call on the voltage drop Tim... 

[nrt69]

is that connector pictured above...upside down?
i just pulled the wire harness(s) and discovered i have a melted wire on the center section, bottom left terminal connection (as if you were looking at the firewall from the front of the car). it would be the same one as above if i turned it upside down.

could that really cause a severe discharge??? I hope its that easy of a fix.

I also need to check the back of the ammeter gauge for meted wires, too, right? I thought i read that somewhere.

[grdprx]

It's most likely upside down, I just pulled it off the firewall and out from under the dash; didn't really pay attention to which way was up.  There is a big triangle on one end that you can match for reference.

It's not the easiest fix, electrical is a bit harder to deal with compared to the mechanical stuff, for me at least.  I need to replace the plastic bulkhead connector which involves taking each wire out and rewiring it in a new bulkhead.  If your bulkhead isn't in real bad shape, you may be able to just fix the terminal so you get a good connection on it. 

If you currently have a bad connection there, the full power of the alternator won't be able to flow through.  I don't recall if wires melt back behind the ammeter, but I know those connections need to be tight.

[nrt69]

no, its right side up. My melted wire is the bottom left terminal of the center section which is the DBL wire going to the volt regulator. yours is the bottom second from left terminal of the center section which is the BLK wire going to the alternator and the top right of the center section which is the DBL wire going to the starter relay...according to my wiring diagram

either way, what would cause these specific wires to melt?

[Charger RT]

no, its right side up. My melted wire is the bottom left terminal of the center section which is the DBL wire going to the volt regulator. yours is the bottom second from left terminal of the center section which is the BLK wire going to the alternator and the top right of the center section which is the DBL wire going to the starter relay...according to my wiring diagram

either way, what would cause these specific wires to melt?

in grdprx case poor outdated engineering. These cars melted these connections in the 60's with stock amp alternators. Now a days no one has the stock 1960's alternator and the increased amps burn it that much faster.

Mopar loved using the amp meter past its prime. In this setup the path to charge the battery is way to long. flow from alternator to battery goes from alternator to amp meter to starter relay to battery. probably 15 feet of wire maybe more. The wire gauge was minimum for the stock amp units and the connectors were of poor design. With a higher amp unit things melt faster.

In modern cars the alternator uses a short run right back to the battery. Volt meters have replaced amp meters. If an amp meter is used it is used with a shunt. (there is a thread we talked about shunts if you want to read on it)

So there are 2 thoughts here one is to run The parallel circuit Nacho favors. It adds wire to decrease to load on the factories poor design. It improves voltage inside the car as well. The only down fall is the amp meter is rated for the stock amp unit and if the wrong sequence of events occur it could burn out the amp meter.

I don't care if the amp meter works or not so when I put my car together in 2000 I needed to do minor bulkhead repair. I run a 60 amp alternator and I just ran an 8 gauge wire from the alternator to the battery. What this does is stops the power generated for battery charging from having to go inside the car then back out and the 2 wires that do go inside can just share the load needed inside the car. This does stop the amp meter from working and prevents it from burning out from a high amp charge. I wish the restoration parts industry would make a volt meter that would bolt into the amp meter location and look like a stock gauge.
Tim

[nrt69]

ok, but theres still more questions to be asked:
1. why has my car worked fine for the past 20 yrs? (i had some discharging issues but not as bad as right now w/my new engine) the only difference for me is a new MSD ignition with the balalst resitor bypassed.
2. can a simple melted terminal to the volt regulator cause a severe discharge (in my case) and if so, how/why?
3. if i ran a wire straight from the alt to the batt, how would i know if it is charging without the ammeter gauge?

[68neverlate]

no, its right side up. My melted wire is the bottom left terminal of the center section which is the DBL wire going to the volt regulator. yours is the bottom second from left terminal of the center section which is the BLK wire going to the alternator and the top right of the center section which is the DBL wire going to the starter relay...according to my wiring diagram

either way, what would cause these specific wires to melt?

If you're sure the melted wires are the ones going out to the voltage regulator, I have a possible scenario for you.  Those wires are only protected by a fusible link.  It's possible if the voltage regulator had a short to ground (the points style regulators are open in the back and could short to the firewall if anything falls behind them), the increased current flowing through those wires could have melted at the connection (especially if the bulkhead connections were bad) before the fusible link blew. 

If that was the cause and you want to be sure that the same thing doesn't happen again after you get everything all fixed and back together, you may want to check that the regulator doesn't have a short to ground...     

[68neverlate]

ok, but theres still more questions to be asked:
1. why has my car worked fine for the past 20 yrs? (i had some discharging issues but not as bad as right now w/my new engine) the only difference for me is a new MSD ignition with the balalst resitor bypassed.
2. can a simple melted terminal to the volt regulator cause a severe discharge (in my case) and if so, how/why?
3. if i ran a wire straight from the alt to the batt, how would i know if it is charging without the ammeter gauge?

Tim and nrt69... it's possible to have the best of both worlds... an operating ammeter that's not at risk of being overloaded and no discharge state.  See here for the thread documenting modifications I made to my car: 

http://www.dodgecharger.com/forum/index.php/topic,84766.0.html

Everything worked exactly as expected for me.

nrt69, there are a number of reasons why you could be in a discharge state... poor battery, poor alternator, not enough alternator capacity for what you have in the car (ie: stereos, electric fans, electric fuel pumps etc.), poor connections that create resistance (heat)... you have to look at everything all together. 

The straight wire from the alternator to the battery would pretty much render your ammeter unworkable, but it would prevent a lot of the current going through that fiewall connector.  You could do what I did in the thread above (a lot more work) but it might be worth it in the long run if you goals at the end are the same as mine were...

   

[nrt69]

68neverlate,

ive read your post but you mentioned the alt was the culprit initially. Ive got a new 78amp alt, new batt, and a new volt regulator. no additional electronics. the wiring is old and crusty but again, i just started having the constant discharge recently after driving the car for 20 yrs. it never charges now. it used to discharge occasionally with the lights, but charge when giving it some gas. now it only discharges and nothing works on the car (slow wipers, no window squirters, blinkers intermittent, etc). Im all for trying to fix the low output at idle issue but i would first like to know why my car jsut started doing this and why it wont charge at all even under throttle. im getting 12.4 volts when checking the battery.

[68neverlate]

OK, so new 78 amp alt, new battery, new reg, new MSG ignition, bypassed ballast resistor, 12.4 volts at the battery, original factory wiring, melted bulkhead connector (at reg double blue wire connection) and discharge state even under throttle.   

Some questions to help diagnose:

    1)  What is the voltage at the output post of the alternator (car not running)? 
    2)  What is the voltage at the output post of the alternator (car running)?
    3)  Is your battery being drawn down at all?
    4)  What is the capacity of the new battery?
    4)  How exactly did you bypass the ballast resistor (which wires did you connect/disconnect to bypass)?
    5)  Which wires were melted at the bulkhead connector (if any)?
    6)  Are there any visible signs of overheating at the ammeter (behind the instrument panel)?

Red flags are going off on the higher output alt with the original factory wiring.  You mentioned that you are seeing a discharge state, so I assume that means your ammeter is currently working.  Answers to the above should help in determining what's going on...     

[nrt69]

hopefully im not hijacking the original post and this is related to what is being discussed here....

1)  What is the voltage at the output post of the alternator (car not running)?
havent checked. can i do this with a hand held volt meter?
2)  What is the voltage at the output post of the alternator (car running)?
same as above
3)  Is your battery being drawn down at all?
yes, eventually. i know because the MSD wont send enough spark to the plugs to fire the car up and when i put the charger on my batt, it takes a while to charge it back up.
4)  What is the capacity of the new battery?
you mean cranking amps and reserve capacity? 750/935/130
4.5)  How exactly did you bypass the ballast resistor (which wires did you connect/disconnect to bypass)?
i simply unplugged one side and connected it to the other side. my ballast had two prongs. one side with two wires and one side with one..forgot which wires they were exactly right now without having my diagram in front of me.
5)  Which wires were melted at the bulkhead connector (if any)?
it was the DBL wire going to the volt regulator.
6)  Are there any visible signs of overheating at the ammeter (behind the instrument panel)?
haven got to that yet but im planning on checking that the first chance i get.

[68neverlate]

Yes, voltage at the alternator output stud can be checked with a hand held volt meter... those are the readings that are most relevant to determining what's happening.