everything is new, but still won't charge...

[71wongbed]

So, I have had this problem for a little while and thought I had fixed it, but I was wrong.
My battery is not being charged by my alternator. I have replaced everything: alternator, ext. voltage regulator, battery AND re-wired the sucker, but it still won't charge. I have eliminated shorts (pulled NEG off battery and from cable to post reads 0V). I had Autozone test the brand new alternator 4 times and it passed, and I disconnected the POS off the back and read 1.5-2+V output, depending on engine speed. Like I said, I built a new harness- the only difference from my harness and the one in the beautiful PDF that floats around is that there is no fusible link between the POS on the battery and the red wire that feeds to the alt, reg, dash so on. Is the fusible link going to keep it from charging?
While running, I test the red on the back of the alt and it just gives me the same reading as the battery. No more, just usually 12.4 or less, depending on the charge of the battery. This is honestly killing.
I know it is hard to help troubleshoot over the net, but any suggestions outside of replacing the truck will help immensly (I plan to call Car Talk as my next step so if anyone could offer any advice that would keep me from that shame...)
Thanks!

Reuben
71 C-20, 350/350, nothin' special

[Twisted78SS]

I would suggest some more testing. Have you tried this?

FULL FIELDING AN ALTERNATOR
A full field test will force an alternator to produce maximum current.
When full fielding occurs, an alternators internal or external voltage regulator is bypassed, causing full alternator output. By providing full battery power to an alternator's field coil via full field test, the alternator will charge at full capacity, providing the alternator is not the cause of any charging related problem.

If the alternator is capable of producing full output during full fielding, the voltage regulator may be to blame for charging-system problems. However before replacing an external regulator. All the wires connected to it need to be checked with a voltmeter to ensure they have correct electrical values. If an internal voltage regulator is used and the alternator passes a full field test. you may want to consider replacing everything at once because if one component is worn out. the others aren't be far behind.



I got this from one of my books,

How to Diagnose and Repair Automotive Electrical Systems By Tracy Martin

[Andy4639]

If it's a external voltage regulator then I would suggest that it was the problem.

[68gmsee]

(I plan to call Car Talk as my next step so if anyone could offer any advice that would keep me from that shame...)

Could use some more info... Is the truck wiring completely stock?

If so, more than likely it's the voltage regulator. I also have seen grounding problems do some weird things.

If the truck has been rewired and you don't plan on redoing it to stock, than I would go with the single wire alternator and be done with it for now. I have one on my farm tractor and it has worked great for about 8 years. I used to have one on my 69 chevy but decided to convert to internal regulator alternator (just happened to have one laying around).

[texanidiot25]

Internal regulated = pain free, cleaner looking, less wires.

[truckdude239]

follow this tread cost me about 120 buxs with a new alt and external reg. and mine still did not work right so i followed this tread http://67-72chevytrucks.com/vboard/s...d.php?t=119379 the internal alt cos tme 40 buxs never had any problems since

[Andy4639]

Check the alternator wire on the back. Big red wire with a volt meter and see if you have more than battery voltage there. With everything hooked up as suppose to be in the truck. Then check to make sure the two smaller wires are correctly positioned on the terminals of the alternator.
Also make sure the belt is tight and it's spinning the pulley. I have had this happen to me before.

[sflanagan]

You can buy stuff brand new out of the box, for example (voltage regulator) and it may not be functional. Dont ask me why but sometimes this does happen. It happend to me. I just went down and grabbed another and she was fixed. Not saying this is your problem. Just food for thought...plus its the cheapest fix to start with...

good luck.....

[71wongbed]

Thanks everybody!
I have replaced the regulator twice in two days, so I'm guessing they wouldn't give me two bad brand new ones, but I could be wrong...
The wiring is not stock, I re-made a harness for just the charging system that looks exactly like the wiring diagram. Wires test good all around and I don't have a ground anywhere.
I suppose it's time to just convert to an internally regulated alternator, and hope that solves it.
I appreciate the help! I still kinda hope Tom and Ray (Car Talk) call me....

[67ChevyRedneck]

You may have a draw when the engine is off which is killing your battery.

[Musclerodz]

If you do not have voltage to the field side of the alternator, it will not charge. Where are you connecting the ground wire to your regulator?

[Wrenchbender Ret]

I think you may not be getting a signal from the ign. switch to the regulator. I believe it is the brown wire. When you turn on the switch you should have current at that turm. although it wont light the test light real bright because it comes through a resister or dash bulb. If it uses a light for charge indicator, it could be a burned out bulb.

[71wongbed]

I think Wrenchbender is on the right track. I have traced the brown wire to a brown/white wire coming out near the ignition switch. Right now it is not connected to anything. I am looking at the wiring diagram, but it is hard to tell where it connects and I have an aftermarket switch wired in. Does this brown/white need to be wired with some kind of resistor? My battery gauge has never worked in the two+ years I've had the truck. How could I wire this brown/white wire and make it work? Does it wire across a resistor to a 12v source or a ground? I think this is the missing piece and if I can wire it any way possible this may fix it! Help!
Thanks!

[71wongbed]

Got it!

The brown wire coming off the ext. voltage regulator was not connected to anything inside the cab. Reading around I found that it is supposed to connect to the ign switch and get excited when the truck is started- if I am wrong, please let me know-

I connected it to my switch, started it and the alternator is now reading 15.7v while running. I know that is kinda high, but is there a way to get it to put out less? Is this going to cause serious damage?

Also, now when I disconnect the NEG cable off the battery, and put my meter from the cable to the post, it starts with a jump showing 10v then slowly counts down to about 0.13v. Is this normal? If I disconnect the alternator it then reads .08v, and when I disconnect the alt and regulator it reads 0v. Is this going to drain my battery or are the alt and regulator just "winding down" and slowly using a bit of voltage? I'm confused...

[68caliRat]

Don't worry about the 15.7 volt charge reading that's fine. As for the reading while the cable is off to the post? Getting a standing voltage reading isn't a problem, what you really need to know is if there is amperage flowing. If you don't know how, I'm sure I could come up with a basic how-to. Doing an amperage read wrong can a will fry your meter, so if your not sure don't do it. I'm sure one of us can explain how if you'd like. Words are great but pics make it easier.

[VetteVet]

Yes the brown wire needs to go to the ignition switch on the ignition terminal. If you had a charging light the brown wire would go to that and the key switch would feed the light. If I read your post right you have the battery gauge so the br wire goes to the key and no resister is needed. The regulator coil provides the resistance. Now when you convert to the internal regulated alternator you will need to install a 80 ohm 5watt resister that you can get at radio shack for a 1.00 or so, between the brown wire and the alternator plug.
15.7 volts is a little high but as your battery gets charged this may drop. I don't think it will present a problem and yes you can adjust it but it requires pulling the cover off the regulator and bending the points spring tab so that the coil will open the points sooner. I don't think you need to do that nor do I recommend it unless you know exactly what you're doing.

why are you reading voltage drop on the negative battery terminal? You should be reading Milliamps?
Is your battery gauge AKA the ammeter working? If not it is not an issue, That's a whole nother problem .

You guys need to hang out at the electrical forum. This topic gets discussed at least once a week.

[Wrenchbender Ret]

I think 15.7 is way too high.

[Billhillys]

I have a 1971 Chevy truck with the same problem have brand new battery ext voltage regulator and alternator and cannot get a charge to my battery all the wires to the ignition have power don't know what else to do
Posted via Mobile Device

[RichardJ]

The frame of the voltage regulator must be grounded or the Alt output voltage will be high.

Connect one side of your volt meter securely to the battery Neg post. Measure the voltage to the truck frame, to the engine block and to frame of the voltage regulator.
You should get readings of 0.0V to all grounds and between all grounds. Any voltage above 0.0 V indicates a bad or missing ground.

If you mounted the voltage regulator on the original rubber "well nuts", you must have a ground wire attached. The rubber pads are for vibration isolation, not electrical insulation.

[RichardJ]

Do not. DO NOT ever disconnect the battery cables when the engine is running on a car with an ALTERNATOR. In the first place, it can damage the alternator and if the regulator is the newer type, solid state regulator, you can blow that as well. Second, removing the cables will provide no troubleshooting information.

Did you build a new under dash harness or just the engine harness? The original 10 Ohm resistor is a resistance WIRE from the Ign switch to the firewall connector. The connecting wire from the firewall connector to pin #4 on the regulator is a copper wire.

The drawing below is one of VetteVet's. The two fuses in the diagram go directly to the ORIGINAL Battery Meter (Ammeter) and no where else. No ground, just the two meter posts

[71swb4x4]

This thread is 7 years old. Billhillys, start a new thread for your problem, you will get more help that way.

[RichardJ]

crap, I didn't notice that.
I wish this and other forums would block posting on an old thread. They could set a time limit, say 6 months. After that point, Someone like Billhillys could start a new thread, linking to the old thread. That would start a new conversation that would be more useful.

Thanks hillbilly for wasting my time.

[CG]

Dunno how it was a waste of your time. I see old threads pop up all the time, I shoot to the newest posts on an old thread to see whats up. I thought your answers were informative, thanks! Looks like Billyhillys is a new user and did what everyone asks ... do a search first.

[VetteVet]

Originally Posted by CG

Dunno how it was a waste of your time. I see old threads pop up all the time, I shoot to the newest posts on an old thread to see whats up. I thought your answers were informative, thanks! Looks like Billyhillys is a new user and did what everyone asks ... do a search first.

times 2 for me. He'll come back to where you answered his post and get your great advice.
The thing that frustrates me the most is when someone makes a post and doesn't give any details on the year of his truck, or the engine size, or any of the pertinent details.

The down side is that we usually read the whole thread until we get to the last poster. I think that's what Richard means by wasting his time. In addition to that we get to read about two or three other problems in the thread that were solved and are no longer applicable.

To Billy:
Don't be offended, Richard is a great guy and very knowledgeable he has helped a lot of the members here. VV

[RichardJ]

71wongbed had a unique problem partly owing to the fact that he made up his own harness from scratch.

hillBillys problem is only similar in that his alternator doesn't charge. The history of what led to his problem is only unique to his truck. Anyone helping him is going to have to ask the questions pertinent to his truck and problem. It is even possible the problem could be the same, but you still have to go through the same question and answer troubleshooting to get to any solution.

When you're dealing with 50 years old trucks, things are screwed up because of age and people with good intentions, screw things up. Old vehicles can be like a box of chocolates.

I would prefer people start a new thread for their own specific problem. If they found an old thread that they think is pertinent, then by all means, provide a link to it. Otherwise, it's just thread hijacking.