I have a 65 Coronet that I recently bought and I am trying to sort out my last issue with it. I put on a set of dual electric fans and 26 inch radiator to keep it cool and settled that issue. My first night out with it the voltage regulator went out. It had a stock type points regulator on it. Right now it has a square back parts store alternator on it. I switched to a stock looking electronic voltage regulator yesterday and it is charging again, KINDA. It is only showing around 12.6-12.8 at the battery at idle, if I rev it up it goes up to 14.3-14.5 but right back down at idle. This is with the fans off. I have a new Power Master 17509 75 amp alternator to put on it but am I going to accomplish anything by doing this. Power master instructions also show to ground the extra field terminal. Right now I just want to get out and drive before the season is up but 12-8 volts without the fans on is not going to cut it. I guess my questions are.
Do I need to install a 1 wire alternator with internal regulator.
Do I need to use the one I have and ground the extra field wire.
Do I need to run a 8 gauge wire directly to the battery.

This is normal and is due to the speed of the alternator / pulley ratios



First question is what do the fans draw current wise?

Then add headlights, A/C, and other things that cause a higher draw current wise.
Now you have established what size (output wise) alternator will be needed.
Once taht is established the next step is the wiring side of things v

I don't have AC but the fans draw 12 amps each, the only other thing is the headlights. I would like to add AC in the spring but it probably wont happen

I have 100 AMP Powermaster alternator. I have SPAL 2700cfm electric fan, and A/C. With eveything on, including headlight, gauge shows little over 13. I do have it grounded with using a seperate 6 gauge battery cable. If I ever have to replace the alternator, I will go higher than the 100 AMP.
Jack

are you using a 1 wire Power master on yours. I am not against buying another alternator, I just want to drive it. The 12.7-12.8 at idle is with nothing on, not even the fans. I do have the Mopar electronic ignition on it.

Also what does it accomplish by grounding the extra field wire. Power Master shows to ground it but that just don't sound good.

Yes, it's the Powermaster 1 wire. Steady 14 reading without AC on.

Can't have too much ground. I didn't notice that PM recommended it, I just thought was good idea, so I grounded it.

I did put the PM alternator on. Im still not happy with it at idle. its around 12.8-13 volts at idle without anything turned on. with the lights on it idles around 12.4. if I give it gas it goes up fine. just not enough at idle. I started it with no ground on the field wire and it didn't charge at all. I put a 10 gauge wire on it and it started charging. do you know what the part number is on your alternator. My old 68 Charger had a painless harness in it I switched the alternator on it to a mid 90's truck 135 amp piece because of the huge fuel pump on it to feed the Procharger.

You either need a smaller alternator pulley, larger crank pulley or turn your idle speed up.

I just converted my 51 Plymouth to 12v, used a Mopar alternator and regulator, 87 Diplomat donor. 13.8-14v at idle. If I turn everything on (not much to turn on) it stays there.

The older factory alt did not put out full charge at idle. Even the output test in the service manual says run the eng at 1500 to 2000 rpm. But the newer Power Master should charge good at idle. We put this one wire 100 amp Power Master alt on my sons Dart and it puts out much more at idle as it put out 70 amps at idle when I put a load on it. We like it because it looks like a stock Mopar alt. You don't have a larger alt pulley on the car do you ? Many racers put the larger alt pulley on for more hp but it kills the charging at idle. Ron

It has the stock pulley on the parts store alternator I took off and the power master has there aluminum pulley. looks to be stock size. I am not against running a 100 amp 1 wire if it will take care of the issue. I do want it to look like a factory alternator.

Sorry, do not know the part number. It's been on the car over 10 years, maybe 15.
Jack

I just seen also that CVF racing offers there own 100 1 wire alternator that they advertise to be designed for low RPM charging. I am running there pulleys and brackets so I looked at there site to see what all they offer. They are definetly proud of them though. they are on sale right now for $255. regular is $319. Im going to see if I can find the part number for the Power Master alternator.

large pulleys on racing cars keep bearings safer at high rpms

I found that out about 15 years ago. I had a 70 Cuda that I put a 426 Hemi. Every time I really got after it I had to put a alternator on it. You would think it would turn 8000 rpm more then once before it took a dump.

per what I have read I think is good to let you know for those don't know:

The need for ground one of the dual prongs alts to be matched to earliers charging systems is because both are isolated. Rotor needs to get both fields to be able to produce electricity.

On earliers systems ( mech reg ) with one wire for field, this wire ( green ) provides a positive regulated source while the other brush is attached directly to chassis. this closes the field circuit to rotor.

on dual prongs with two wires ( elect reg ), one wire ( blue ) provides constant positive from ign switch, while the other one ( green ) is now a negative regulated source. Hence the reason to be both isolated.

There is somehow of myth about "one wire alts" being more efficient... false. is not because is a "one wire alt" but because the alt itself response better or not to the regulator or regulator is more efficient.

stock look "one wire alts" are not that the same alt with a MOUNTED ON regulator. any of us can become the stock alt into a One wire alt just getting this regulator:



which is available at several dealers. this uses just a ground source, positive source and is triggered to ON from a stator lead

Do you by chance have the part number for this? I need to figure out if it will fit in the space I have for it.

My only tip to you about the PowerMaster Alternator is this. If you think the belt is tight make it tighter, they don't charge well with a loose belt. I had a "not charging" issue with mine, I tightened the belt and it helped. I think it could stand to be tighter. PowerMaster assured me that you can't get it too tight and it won't kill the bearings.

FWIW I just changed out my Powermaster alternator (I think it was a 85 amp one) for a new 125 amp Powermaster.

My car was doing exactly what yours is and finally started trying to charge all they way up at 16 volts...Lights dim at an idle but everything worked fine once off idle...

With the stereo load I have when it is turned up I know the 85 Amp didn't keep up with the draw...I bolted the new 125 amp alternator on the factory brackets after making all new spacers on my 383.

It's a world of difference...no more low charging at idle as the gauge reads a consistent 13.8 all of the time...

The added amps allow me not to drain the battery while driving with the music cranked up...

I think the bolt on voltage regulator on mine was bad since the alternator does still charge...That may be your issue also...