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100 amp alt, what kind?
https://slantsix.org/forum/viewtopic.php?t=6203		 Page 1 of 2
Author:  Jopapa [ Sun Jul 06, 2003 9:33 pm ]
Post subject:  100 amp alt, what kind?
For installing a 100 amp GM one wire alt, would it still wire into the stock voltmeter the same way as the stock Mopar high output wiring does (wire from amp output to voltmeter negative, then from voltmeter positive to fusible link to battery positive)? Would 14 gauge wire be sufficient?

Then once that's done, how would I go about removing the Mopar voltage regulator and dual field wiring from the harness without hurting anything?
Author:  Pierre [ Sun Jul 06, 2003 10:46 pm ]
Post subject: 
There were stock voltmeters? I thought they were all ampmeters... the way you are describing the wiring is if the meter was measuring amps, not volts.

And no, 14awg for 100a is no where near safe. I would run at least 4awg for that much current, you might get away with 6 or 8 depending on type of wire used. When I installed my 200a gm powermaster one wire unit, I ran a 2awg welding wire from the alternator directly to the battery, and just taped up the ends of the original alternator wires. I removed the regulator, and secured the conencter so it wouldn't flop around. I did not bother removing the wires, that would be a royal pain to undo the tape on the harness etc... and figured if for any reason I need to install the stock system again I can just plug and play.

By the way, how are you bolting the alternator up? Did you make your own brackets? If you want only 100a I believe powermaster makes one in the original mopar case so you don't need to modify anything.... (also comes in 1 wire version if desired)
Author:  Jopapa [ Sun Jul 06, 2003 11:25 pm ]
Post subject: 
Quote:
There were stock voltmeters? I thought they were all ampmeters... the way you are describing the wiring is if the meter was measuring amps, not volts.

And no, 14awg for 100a is no where near safe. I would run at least 4awg for that much current, you might get away with 6 or 8 depending on type of wire used. When I installed my 200a gm powermaster one wire unit, I ran a 2awg welding wire from the alternator directly to the battery, and just taped up the ends of the original alternator wires.
Yeah at least I assumed it's for voltage since it's not labelled one way or another (just says "ALT"), it moves and positions itself according to what voltage and drain would be when the car's running, and most vehicles I see measure voltage.

As far as the wiring, self-professed electrical nitwit that I am, I wondered if since 16awg is sufficient (going by the guid here: http://www.allpar.com/fix/alternator.html) for a 65 amp alt (I'll be putting in 14 just to be safe), 14 or 12 would be safe for a 100 amp. Glad you corrected me on that. I've got all the wiring I'd need on hand in every gauge 8)
Quote:
By the way, how are you bolting the alternator up? Did you make your own brackets? If you want only 100a I believe powermaster makes one in the original mopar case so you don't need to modify anything.... (also comes in 1 wire version if desired)
Well I had wondered what the best year to get a GM alt from was as far as reliability, output at idle RPMs (my truck has a Beck/Arnley 120 amp and it doesn't put out well at all until 900 RPMs when cold and 12k RPMs hot), and mounting up the housing. It'd be nice if I could just buy a bracket and bolt it on. Does anyone make GM brackets for /6 engines?
Author:  Pierre [ Mon Jul 07, 2003 12:23 am ]
Post subject: 
Thats a negative on the brackets. Check out this thread for the brackets I made for my powermaster/gm case unit
http://www.slantsix.org/forum/viewtopic ... ator#26749
Author:  Jopapa [ Mon Jul 07, 2003 11:17 am ]
Post subject: 
Pretty good setup. Gotta love the blue color :P

I saw that Powermaster makes a direct bolt-on 200 amp alt, but I would think that'd be a little unnecessary overkill for even any street rodding (and she doesn't have a big stereo system in there either).

Oi, decisions decisions...
Author:  Chuck [ Mon Jul 07, 2003 11:25 am ]
Post subject: 
If the dash gauge is a voltmeter then 16ga is fine. If it is a current meter then you need much larger. The way to tell is to disconnect the wire from the gauge. If everything still works (except the gauge) then it is a voltmeter. If you disconnect a current meter, most the the electrical system will be disconnected.

I wouldn't bother removing the wiring for the old regulator.
Author:  Pierre [ Mon Jul 07, 2003 11:30 am ]
Post subject: 
Bolt on my @$$. This one was supposed to be bolt on, # 8-47539 (thats the one you see in the pictures) but it was no where near close. Other then the ones powermaster offers in our original cases, the only other one I can see as being "bolt on" would be # 43311. Infact if I were to do it all over again, I would probably use # 43311 because it would probably only require some washers for alignment, no brackets.
Author:  Jopapa [ Mon Jul 07, 2003 2:05 pm ]
Post subject: 
Quote:
Bolt on my @$$. This one was supposed to be bolt on, # 8-47539 (thats the one you see in the pictures) but it was no where near close. Other then the ones powermaster offers in our original cases, the only other one I can see as being "bolt on" would be # 43311. Infact if I were to do it all over again, I would probably use # 43311 because it would probably only require some washers for alignment, no brackets.
Pretty spendy stuff. I think Something of either 80 or 100 amp would do her just fine. I'm trying to prioritise the jobs to be done on the car by price and necessity. Right now 500 bucks would be much better spent on a head rebuild and a new exhaust.
Author:  Jopapa [ Mon Jul 07, 2003 2:10 pm ]
Post subject: 
Quote:
If the dash gauge is a voltmeter then 16ga is fine. If it is a current meter then you need much larger. The way to tell is to disconnect the wire from the gauge. If everything still works (except the gauge) then it is a voltmeter. If you disconnect a current meter, most the the electrical system will be disconnected.

I wouldn't bother removing the wiring for the old regulator.
Well I do know that the gauge is wired between the alt and the battery, and that the system is dual field. When I left the gauge disconnected the car wouldn't start since the starter relay had no circuit connected, but IIRC the dome light was on.

BTW what the heck is the point of a dual field system?
Author:  kesteb [ Mon Jul 07, 2003 2:12 pm ]
Post subject: 
You will burn out the stock mopar alt gauge with a 100a alternator. It was only designed to handle 60a max.
Author:  Volaredon [ Fri Jul 11, 2003 10:05 pm ]
Post subject:  regulators
Burn out a regulator w/over 60 A? Maybe the old point ones, but I have swapped in the old late '70's thru the '80's Chrysler 100A alternator with absolutely zero regulator problems, although on my 79 Ramcharger, I melted the amp gauge the 1st time that I went to jump another car and gave that new 100 A an excuse to work! Bought a Stewart Warner -100/0/100 ammeter and although it took a LITTLE dash surgery, really not bad, I put it in the same place as the stock one, I never had that problem again. REMEMBER- Anyone out there that has ever tested a Mopar charging system with the likes of a VAT 40, or full field tested one, the regulator does its job by regulating voltage, not amps, it acts as a variable resistor, by controlling the ground via one of the 2 brushes in the alt. By grounding the side terminal at the regulator, (check the wire colors at the alt.,you'll see the same wire there, too. The wire at the middle of the reg. connector is the battery(+) feed so the reg. knows how much to restrict the ground to the other wire. When you full field test a system, you NEVER wanna ground that center wire, ALWAYS the one to the side of the plug.
Over voltage causes you to go thru water in the battery like crazy and your light bulbs won't last either, but remember that a circuit will only use the amps it needs even though there may be more available. If you put in a 450 amp battery, this time of year, it will probably start your car OK. To swap in a 1000 amp killer battery, even though there may be 1000 amps available, it will only draw what it needs, NOT the whole 1000 amps.
Anyone familiar with a scope? Regardless of the coil capacity, look at your pattern with worn plugs, then again with the new ones in. Takes alot less juice, right? But that coil is still CAPABLE of high output when needed..
Author:  Jopapa [ Sat Jul 12, 2003 1:24 am ]
Post subject:  Re: regulators
Quote:
Anyone familiar with a scope? Regardless of the coil capacity, look at your pattern with worn plugs, then again with the new ones in. Takes alot less juice, right? But that coil is still CAPABLE of high output when needed..
I keep trying to get her dad to teach me how to use his old scope...
Author:  bud L. [ Sat Jul 12, 2003 3:04 pm ]
Post subject:  ?
speaking of scopes , I have an old Sun tune-up machine w/ scope. But the scope doesn't work does anybody out there have or no somebody capable of fixing it?
Author:  Chuck [ Sun Jul 13, 2003 3:48 pm ]
Post subject: 
Quote:
Quote:
If the dash gauge is a voltmeter then 16ga is fine. If it is a current meter then you need much larger. The way to tell is to disconnect the wire from the gauge. If everything still works (except the gauge) then it is a voltmeter. If you disconnect a current meter, most the the electrical system will be disconnected.

I wouldn't bother removing the wiring for the old regulator.
Well I do know that the gauge is wired between the alt and the battery, and that the system is dual field. When I left the gauge disconnected the car wouldn't start since the starter relay had no circuit connected, but IIRC the dome light was on.

BTW what the heck is the point of a dual field system?
I don't think there is actually a "dual field" system. The alternator that I am used to has two field wires instead on one. This is because this alternator does not have one of the field wires grounded. This is just an engineering design preference for the electronic regulator system installed in the 70s. The system could just as easily have used the grounded-field alternator, as obviously the after-market electronic regulator does for the old alternator. The later alternator can be used with the old system by just grounding one of the field terminals on the alternator.

And the regulator DOES alter current through the field to regulate the output, as a transistor is a CURRENT device. Since the resistance of the field stays the same, the voltage across the field coil will increase as the current through it increases (E=IR). (Not that you really need to know any of this.)
Author:  kesteb [ Sun Jul 13, 2003 9:29 pm ]
Post subject: 
Heres an articule on how to bypass the stock ammeter. http://www.madelectrical.com/electrical ... uges.shtml

They also advocate using the 3 wire GM alternator as a superior alternative to the 1 wire.
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