Alternator output 25v-50v !!!!

[andben]

Hi, I have some problems with my '70 Charger. When I check the output on positive on alternator is says between 25v (idling) to 50v when accelerator pedal is pushed.

I have bought a new voltage regulator and tried another alternator as well but the output is the same. It is NOT connected to the battery positive of course. I will probably blow up battery or roast my wires.

Green and blue is connected to alt from voltage regulator on the firewall. When I disconnect those cables on the alt the output drops to 0v.
I got 12v ignition current on the blue one and green is ground I think.

Can someone help me out?   

[Nacho-RT74]

once I had a fail like that... 18 to 24V iddiling and discharge on ammeter. When revving up, allmost 40V and then began to registry a charge

it was one of the rotor vent vanes getting friction with one of the stator leads and making a pulsating short.

HOWEVER you say tried another alt...

dunno. just giving my experience

P.S.: yes, blue is ign switch signal, and green is regulated ground from regulator

[Pete in NH]

Hi,

I'm not sure what you would measure on the alternator output stud with the battery disconnected. You are essentially running the alternator with out any load. What do you have disconnected? If it's the black wire to the alternator output stud, the output voltage could be quite high as there is no voltage feedback to the regulator. I'm curious as to what prompted you to try running it like that. Could you describe what the initial issue was.

[A383Wing]

what does voltage measure at the battery? I'm gonna say you are not getting power back to battery and alt is running wide open because it cannot see battery being charged

[andben]

Ok thanks guys! Appreceiated!

I bought the car from the states, of course, and when it hit Sweden I tried fire it up but it was dead. Used to be battery but his one WAS dead. Completly.
I directly started to troubleshoot firewall/bulkhead connector and there it was, meltdown. After rewire some stuff and some new welded splice it (everything was disconnected) I started the car and checked all lamps, turn signal, hazard, brakes and stuff. Did work. When I checked output of alt it said 27v constantly.
After that I havent reconnect the black wire stud on alt.

So maybe my problem is not a problem? Maybe I should reconnect alt and check firewall/bulkhead for a new meltdown

[Pete in NH]

I would reconnect the black wire to the alternator output stud. Remember to disconnect the negative battery terminal before doing so. Reconnect the negative battery cable and without starting the engine use your meter to see if you now have battery voltage at the alternator output stud. If you do, start the engine and see what the battery voltage is. I think you may have fixed the problem when you fixed the bulk head connector pins.