So the "2nd alternator" is simply filling the void left by a failed A/C compressor? If you wanted to use it for welding I think you would want it to be isolated completely from the vehicles electrical system.

 

No they both create voltage. Somehow they are linked together through a mess of wiring. I have traced it all back and know where it all goes. My problem is just idk which alternator to change

 

Take both of them to be tested?
"mess of wiring" IDK you may be on your own with that one.

 

It is your low volatage light. I was going to say a belt slipping may be the issue but I have no clue with this 2nd alt. The only thing I know of with two alt is some 7.3L fords. Also for welding its easiets to use two batteries together to give you 24v. I saw some rock crawlers do this, pretty ingenious of them.

 

Batteries wired in series will double the voltage but the available amps are the same. Batteries wired in parralel will double the available amps but the voltage remains 12.6 volts.

 

Agreed^

Actually it should be possible. Completely silly, and pointless, but theoretically possible. The"second" alternator's body/ground, isolated and connected to the output of the first would put them in series. Might even be with the second. (delco) regulator grounding on that link, it might even be a go with the unmodified regulators. Completely pointless though.

Maybe he went to a higher, easier to reach delco alternator, and just left the lower stock one as an "idler" pulley. Just using its bearing to rout the belt. Some of those "one wire" delcos will not kick in till they reach a high RPM. I have one in my Jag. Start it and idle, low volts. Rev it past 3,500 or so a sec and she kicks in, and stays kicked in. Needs that first rev. It will never start charging without it.

I've seen at least a few posts of guys swamping there alternators. Them gettn' full of mud and rocks. Maybe that where he was going there. I wonder if it (the lower), still has the stator & diodes in it.

 

this is how its done in a CUCV. well ones that havent been converted to 12V yet lol

 

Well here's how it works... as far as I can tell the stock alternator works. But unless I need to turn on the second one to give it that initial boost. Once I'm driving I can turn it off and the stock one will float the battery at 14 volts. Problem is at idle the volts drop really low only when I am running something. Like the heat or lights. I have never had a problem starting up or anything like that. I just need to know why my volts would dive at idle.

 

Basically even with both alternators running if I am running lights and heat the volts drop at idle. If I am not running anything they do not drop. I can see when I turn on my heat that my lights dim. This cannot be normal in any Situation.

 

I started climbing around under the hoods of cars and trucks at the tender age of 12. That was 28 years ago. I've completely restored several old 60's Mustangs, and 3 different early 70's Chevy trucks. I helped repair an old Corvair and to restore an old International Scout that had more crap bolted and welded onto it than I've ever seen on one vehicle. I'm on my 4th jeep. I've even had a Volkwagen Scirocco and a Mazda RX-7 with their interesting methodologies for making things work.

But you, sir, have presented something I have never seen in my life. And the explanation you've given for the functionality of it all...

Well... You definitely get the Rube Goldberg award for automotive engineering, thanks to the previous owner.



It sounds like if your voltage is dropping once you kill that "slave" alternator, you've got a bad primary alternator or you've got some kind of larger parasitic draw you haven't discovered yet. Maybe something shorting to ground but somehow not blowing a fuse, or some other oddity. Perhaps some kind of electrical heating device that has run wild?

If it were mine, I'd start with rewiring that rig back the way it was intended, taking the second alt out of the loop (at least electrically) and see if you still have voltage drop issues. If so, they should at least be somewhat easier to track down using a DMM and methodical pulling of fuses.

 

Totally normal and expected with a slipping belt! When the regulator asks the alternator to go to work, it needs traction then.

X2! Safe to bet thee PO had some tragic no charge thing in his history. Maybe he was just jetting started? Gotta be room there for a third....

 

its done all the time in car audio

 

?????

Cool, I googled "weld with 24 volts" One guy talks about using a resistor...Guess it's doable!

https://www.google.com/search?hl=en&...pe=&as_rights=

 

I know for hydro applications you can get "standard" auto alternators that put out higher voltage. Maybe allong the line EVIL mentiones, the second one is higher. Heck, could be 110! Are there any modifications to the throttle? Any receptacles!

Also, (seprarely) there's some fancy stuff, something to do with a sensor they tweak to make the weldernator work better. TPS maybe? I forgot.

 

There was a system installed in it before. A very large one from what I can tell. Maybe this is what it was used for. Im going to check the belt. Maybe that guy was right. It doesn't squeak though...