my charging issues 1968 charger

[flathead1946]

I am about 95% done building my charger. I got it to run the other day but its not charging. Everything is new, wire harness, petronix electronic coil and distriburator, Electronic voltage regulator, new ballest resistor, new charging wire harness, rebuilt dash harness, rebuilt restored gauges. new alternator. new battery. when running the guage shows its discharging. removing the positive batery cable and the car dies? Any ideas? thanks in advance.

[Mopar Nut]

Defective new alternator, mine did the same thing when my battery went dead.

[Pete in NH]

Hi,

Could be any number of things. Exactly what type of alternator and electronic voltage regulator did you use? Your 68 did not originally have an electronic regulator so an original type wiring harness will not have the needed wiring paths. Tell us what you are using an we'll get it sorted out.

Also, don't disconnect the battrey while the car is running , it can damage things like your new electronic ignition. It's kind of an old shade tree mechanic way of checking for alternator output but, it can get you into a whole world of trouble especially on newer cars.

If you want to start looking at some things the charge path is from the alternator output stud through a bulkhead connector pin to the dash board ammeter this part of the path is a black wire. From the other side of the ammeter a red wire goes to another bulkhead connector pin through a fusible link to the battery stud on the starter relay and then on to the battery. Do you have a test meter to measure voltages?

[flathead1946]

The alternator is a rebuilt unit from advanced auto, the voltage regulator is one I got off ebay Suppose to be for a mopar. the wire harness under the hood is from year one with the correct electronic ingnition wiring. the dash harness is stock but restored. so was the gauges in the dash. would this cause the problem? I have a meter and will check the voltage when I get home. thanks

[elacruze]

Put your multimeter on the battery so you can see it. <edit> before jumping the alternator you need to know if you have a single-post or dual-post alternator. IIRC one regulator changes hot output, one controls ground return. you need to know which you have.
Disconnect the voltage regulator wire from the alternator field terminal. let the car idle and touch a jumper wire from battery positive to the field terminal on the alternator. The voltage should jump up. If the voltage exceeds 15.5 volts, don't keep the jumper in place or you can damage components. If that test is passed, use the multimeter to verify voltage from the regulator to the field post. Lastly, use the AC scale on your multimeter to test for alternating current; if you have more than 2 volts may indicate a bad diode.

A good read;

http://www.pvv.org/~syljua/merc/TooSeptST07.pdf

[Pete in NH]

Hi Flathead1946,

We just went through something similar to your issue with another member. I need to know specifically if the alternator you got from Advanced Auto was for a 68. Also, need to know specifically what that EBay voltage regulator looks like.

There could be an issue with the alternator field connections. On a true 1968 alternator one field brush is internally grounded in the alternator. Some re-builders are using a terminal on that grounded brush holder that looks just like the one you are supposed to connect the wire from the voltage regulator to. With this set up you get a 50-50 chance of connecting it properly. If you get it wrong, you get no alternator output and possibly damage the regulator.

If you can post photos of the regulator and back of the alternator.

[myk]

Have the 'alt and if possible, the regulator tested.  Wouldn't be the first time a "new" part was bad out of the box...

[flathead1946]

Thanks for allthe replies I wont be able to test anything out till sunday and I will post phots and info here on monday. Thanks again

[flathead1946]

 elacruze ask that I" Put your multimeter on the battery so you can see it. <edit> before jumping the alternator you need to know if you have a single-post or dual-post alternator. IIRC one regulator changes hot output, one controls ground return. you need to know which you have.
Disconnect the voltage regulator wire from the alternator field terminal. let the car idle and touch a jumper wire from battery positive to the field terminal on the alternator. The voltage should jump up. If the voltage exceeds 15.5 volts, don't keep the jumper in place or you can damage components. If that test is passed, use the multimeter to verify voltage from the regulator to the field post. Lastly, use the AC scale on your multimeter to test for alternating current; if you have more than 2 volts may indicate a bad diode. "

Ok so I checked the alternator with a multi meter is shows between 13 and 14 volts at idle. I disconnected the field wire from the alt and used a jumper to the battery. No increase in voltage. what does this mean?

[elacruze]

ok let's be clear.

What is your battery voltage; A, key off. B, engine running alternator connected normally.
What is the voltage measured between the hot post of the alternator and the alt body when; A, idling connected normally. B, idling with jumper wire.

13-14 volts at idle is good. I don't understand what you're indicating when you say 'no change'.

[flathead1946]

is your battery voltage; A, key off. B, engine running alternator connected normally.
What is the voltage measured between the hot post of the alternator and the alt body when; A, idling connected normally. B, idling with jumper wire.

13-14 volts at idle is good. I don't understand what you're indicating when you say 'no change'.

Voltage with car off at the battery is 13.34
Voltage at idle at the battery drops to 12.72
disconnecting the field wire and jumping showed no change in the battery voltage 12.7.

I did connect the meter to batter y side of the alternator and the voltage was jumping all over 13-19 volts. hope this helps.

 

[Pete in NH]

Hi,

A picture being worth a thousand words seeing what regulator , wiring and alternator you have in there is going to be very helpful. Until then, I'm a little confused about some of the things you reported in your last posting. Are you saying you put a jumper between the alternator output stud or battery positive terminal to the field terminal on the alternator but the battrey voltage did increase?

If so, there are two possibilities, one a bad alternator or two an open path in the charging circuit such that the battery is not connected to the alternator output stud. One addition test with you voltmeter- with the car not running do you have battrey voltage from the alternator output stud to ground?

[elacruze]

I'm with Pete, sounds like you may have an open circuit between the alt post and battery. Check your fusible links at the firewall. Voltage fluctuation like you have may be simply your voltage regulator tripping in/out-is it a mechanical regulator?

[MaximRecoil]

Voltage with car off at the battery is 13.34

That voltage doesn't make sense for a car battery with the engine off unless it has very recently been charged. A battery that hasn't been charged very recently will stabilize at about 12.6 volts. A car battery has six ~2.1 volt cells in series, thus ~12.6 volts.

Voltage at idle at the battery drops to 12.72

This is still slightly higher than an at-rest battery should be, and it is especially higher than a battery that is running the ignition system and meeting any other electrical demands there may be in a car with a non-working alternator. How soon after starting the car did you test the battery voltage? For your battery to be at 13.34 volts measured soon after turning the engine off, I would expect it had been charging at about 13.8 volts, which is pretty typical. Keep in mind that a battery has to recoup its losses after starting your engine, and it will take a certain amount of time to get up to full charging voltage (typically 13.8 to 14.4 volts). You say your battery is new, but that isn't an absolute guarantee that it isn't defective or in a state of partial discharge. Have you tried a different known-good battery in the car?

I don't really know what to make of your posts, because some of your information doesn't seem to align with electrical theory.

[flathead1946]

Thanks for everyones input, I ended up replacing the alternator and now my system is charging. The Alternator I changed was a new rebuilt Advanced auto POS. I just posted my next issue, once again thanks for all your input.