When I checked the output of my alternator it read 26 volts. Is that in the correct range as it seems a little high? Amp gauge reads high when idling and maxed out when going down the road. I have replace the bulkhead connector due to alternator wire melting it. Any suggestions much appreciated.
ALTERNATOR OUTPUT
- Thread starter DVO
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No, it should be more in the 13.5-14.5 range. 26 is blowin it outta the water. Don't run it like that.
Tell us about your car .
Year
Model
Engine
Electrical modifications
Post photos of your alternator from the rear showing the wires.
Post photos of he voltage regulator
Year
Model
Engine
Electrical modifications
Post photos of your alternator from the rear showing the wires.
Post photos of he voltage regulator
Nice car but it'll burn down running it like that. Pics of alternator and vr would help.
Sumptin's wrong.
In the other thread I thought you posted 26 amps. (my mistake, guess it was because that thread was about power output)
Tell us how you are measuring this; at the alternator, at the battery, a cigerate lighter gage?
and whatever you know about the alternator and voltage regulator.
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Here's how a '68 Dart alternator was wired from the factory.
The regulator allows current to flow through when it (the regulator) sees less than 14 volts at its 'ignition' connection.
Ignition meaning the ignition-run wiring. How it works is illustrated here.
Possibilities for power continuously flowing into the rotor include: regulator seeing low voltage due to resistance, and regulator getting bypassed (J2A wire connecting to the alternator field terminal somehow)
The regulator allows current to flow through when it (the regulator) sees less than 14 volts at its 'ignition' connection.
Ignition meaning the ignition-run wiring. How it works is illustrated here.
Possibilities for power continuously flowing into the rotor include: regulator seeing low voltage due to resistance, and regulator getting bypassed (J2A wire connecting to the alternator field terminal somehow)
Assuming your charging system is still stock like in mattax's diagrams.
You have a 1 field wire alternator.
The voltage regulator would have to be providing 12v to the field terminal of the alternator. And at that I'm not sure it would produce 26 volts.
Was the alternator fully connected to the system and battery when you tested the voltage
You have a 1 field wire alternator.
The voltage regulator would have to be providing 12v to the field terminal of the alternator. And at that I'm not sure it would produce 26 volts.
Was the alternator fully connected to the system and battery when you tested the voltage
26 volt reading came from the batt post on the alternator with engine running at idle. Alternator is a round back, field wire rebuilt one, vr is new electronic type, wiring is new painless system
one field wire rebuilt one, vr is new electronic type, wiring is new painless system
67Dart273
Well-Known Member
OK split the system (in your mind) into sections
No particular order
1...The field/ regulator circuit
2...The output circuit or "charge path" to the battery
3....The components, AKA, the VR and the alternator
1...You could have something wrong, bad VR, something in the field wiring, that is causing full battery power to be applied to the field, causing the alternator to go to full output. HOWEVER if it actually is outputting 26V to the battey and system, the battery should be boiling, hot, smelly, and puking acid, and you should be burning up lamps and other electric components.
2...The output circuit. In a stock wired car, the output comes off the big stud/ BLACK wire on the alternator, goes to and through the BULKHEAD CONNECTOR, goes in up by the dash cluster where there is a WELDED SPLICE in that black wire, and that splice feeds the ignition switch, the hot fuse buss, the headlight power to the headlight switch, and depending on year, a couple other things, and then goes a few more inches to the AMMETER
Through the AMMETER, out on the BIG RED, goes out through the BULKHEAD CONNECTOR, interfaces with the FUSE LINK, and goes to the BIG STUD on the STARTER RELAY where it junctions and feeds the BATTERY
SO IF YOU HAVE a broken connection in that black wire such as the alternator end eyelet connector, the bulkhead connector terminals, the eyelet terminals at the ammeter, or in the ammeter itself, THE ALTERNATOR OUTPUT will skyrocket, as it is now effectively disconnected from the battery
HOW TO TROUBLESHOOT.
Easy. Connect one lead of your multimeter to the battery + connector. Connect the other to the alternator output stud. Run the engine at high idle and verify that the ammeter shows overcharge. READ the meter. If the meter reads quite a bit of voltage, you have a break in the charge path. If the voltmeter reads quite low, "let's say" no more than 2V or so, then the trouble is in the field or VR
No particular order
1...The field/ regulator circuit
2...The output circuit or "charge path" to the battery
3....The components, AKA, the VR and the alternator
1...You could have something wrong, bad VR, something in the field wiring, that is causing full battery power to be applied to the field, causing the alternator to go to full output. HOWEVER if it actually is outputting 26V to the battey and system, the battery should be boiling, hot, smelly, and puking acid, and you should be burning up lamps and other electric components.
2...The output circuit. In a stock wired car, the output comes off the big stud/ BLACK wire on the alternator, goes to and through the BULKHEAD CONNECTOR, goes in up by the dash cluster where there is a WELDED SPLICE in that black wire, and that splice feeds the ignition switch, the hot fuse buss, the headlight power to the headlight switch, and depending on year, a couple other things, and then goes a few more inches to the AMMETER
Through the AMMETER, out on the BIG RED, goes out through the BULKHEAD CONNECTOR, interfaces with the FUSE LINK, and goes to the BIG STUD on the STARTER RELAY where it junctions and feeds the BATTERY
SO IF YOU HAVE a broken connection in that black wire such as the alternator end eyelet connector, the bulkhead connector terminals, the eyelet terminals at the ammeter, or in the ammeter itself, THE ALTERNATOR OUTPUT will skyrocket, as it is now effectively disconnected from the battery
HOW TO TROUBLESHOOT.
Easy. Connect one lead of your multimeter to the battery + connector. Connect the other to the alternator output stud. Run the engine at high idle and verify that the ammeter shows overcharge. READ the meter. If the meter reads quite a bit of voltage, you have a break in the charge path. If the voltmeter reads quite low, "let's say" no more than 2V or so, then the trouble is in the field or VR
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67Dart273
Well-Known Member
IF YOU do not have a service manual and or wiring diagram, go over to MyMopar.com and download a factory service manual, and then go into the wiring section, and download the 3rd party wiring diagrams. These are NOT factory, but are sometimes easier to follow along with the factory diagrams.
You ment to say 26 v right
Ok I just have to ask...
Questions
- Your voltage testing device is measuring DC volts and you have it on the proper scale ( 20v scale is common to use for cars)
- You know the difference between AMPS and Volts?
- You have a 12v car battery, 24v batteries can be the same external size
Questions
- When you measure 26v at the alternator terminal what does it measure across the battery?
65TerrorCuda
Well-Known Member
If it's really 26 volts that's crazy high. Can a stock(ish) alternator even do that?
My recollection from years ago is that an alternator without a load can put out pretty high voltage like 70V there was a poplar science article, where they took an alternator and hooked it to a transformer and made 120v
Might have removed the diodes???
Might have removed the diodes???
67Dart273
Well-Known Member
No. When you unload an alternator and full field it, the voltage goes to the moon. There used to be these junk switch boxes you could buy to "provide 110v" (lie, the voltage was all over the place, and it was DC, not AC. ) What these boxes did was switch/ disconnect the battery, feed the alternator output to an outlet, and "full field" the thing.
67Dart273
Well-Known Member
Thanks, edited. You meant to say, "meant," right? LOL
So that might answer how the OP could be getting 26 volts at the alternator.
If the output from the alternator was not actually connected to the battery (through any of the typical ways)
And the voltage regulator was seeing low battery voltage because the battery is not being charged.
Maybe it could get to the magic 26v?
Just a thought!
67Dart273
Well-Known Member
Exactly, and on a side story, is why I am SO against the old 2 diode battery isolators. Two diodes, 1 leg of each of two went to the batteries, and the center common went to the alternator. The main battery normally sees hardest use and recharge, so that diode tends to fail. With that diode open, the VR is reading the dying main battery and ramping up the alternator, which is still connected to the aux battery, boiling and charging it to death. That is how you blow up boats
Ok I see a problem.
Early in he says "no electrical mods other than Mallory ignition"
Then a few posts down he says "painless wiring harness"
When will people realize these are GM centric and gm does things different than everyone else, so therefore they really aren't "painless" on other brands ... there is alot of false advertising in their very brand name....
Early in he says "no electrical mods other than Mallory ignition"
Then a few posts down he says "painless wiring harness"
When will people realize these are GM centric and gm does things different than everyone else, so therefore they really aren't "painless" on other brands ... there is alot of false advertising in their very brand name....
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