Replacing externally regulated alternator with one-wire internally regulated alternator

[mkrazy127]

I am not a wiring expert and have been researching replacing the old externally regulated alternator with an internal one-wire alternator. I have a powermaster 1-wire alternator.

When you read everything online for this, most say just remove the old external regulator and then run a heavy gauge wire from the B+ on the new alternator to either directly to the Battery or the battery side of the starter relay. What doesn't make sense to me is how power will be supplied to the rest of the car. If you look at the picture above, the wires coming from the current regulator are marked with a red arrow. Notice the heavy wire from the current setup goes to a junction (horn relay?) mounted on the fender between the battery and starter relay. The other heavy wire I'm guessing goes to the fuse box, so if I remove that wire, nothing will work. If I take and run the B+ from the new alternator to this junction then how will the battery get charged? My thought is that I need to run a 4g or 6g wire to a 100 amp fuse then from that fuse, run a wire to the both the Battery (or B+ side of stater relay) and that junction (horn relay?).

Next question is with the two wires I have circled - are those for the ALT gauge? Is there a way to still have that function? Most things I've read say to just install a volt meter.

The green arrow is pointing to the connector that went to the external regulator. The wires laying on top of the shock tower were what came off of the old alternator.

Thanks for any help!!

 

[midlife]

Two thick wires go to that junction box: one from the alternator and one from the main headlight harness. Your 1 wire alternator simply replaces the one thick wire from the alternator harness.
The two wires appear to be non-factory; maybe related to the MSD?

 

[mkrazy127]

Two thick wires go to that junction box: one from the alternator and one from the main headlight harness. Your 1 wire alternator simply replaces the one thick wire from the alternator harness.
The two wires appear to be non-factory; maybe related to the MSD?

The wires I'm pointing to all go to the external regulator harness and/or back of the original alternator and 99% sure they are all factory. After looking again, I do see a second heavier yellow wire also attached there to the B+ side of the starter relay, so that might be what is actually charging the battery. Both are fusable links. It would have been a lot easier to figure this out if the original alternator was actually working when I started on this. So I'll try just running the new 4/6 gauge wire from the B+ of the new alternator to the B+ of the starter relay.

 

[kevken1959]

The wires I'm pointing to all go to the external regulator harness and/or back of the original alternator and 99% sure they are all factory. After looking again, I do see a second heavier yellow wire also attached there to the B+ side of the starter relay, so that might be what is actually charging the battery. Both are fusable links. It would have been a lot easier to figure this out if the original alternator was actually working when I started on this. So I'll try just running the new 4/6 gauge wire from the B+ of the new alternator to the B+ of the starter relay.

I'm thinking about converting to this: https://www.speedwaymotors.com/Tuff...ooth-Back-Ford-Alternator-100-Amp,278148.html. I've also got the junction post you spoke about. How did you end up hooking the one wire from new alternator?

 

[kevken1959]

Two thick wires go to that junction box: one from the alternator and one from the main headlight harness. Your 1 wire alternator simply replaces the one thick wire from the alternator harness.
The two wires appear to be non-factory; maybe related to the MSD?

Hey Randy. I posted a problem I'm having with my charging system and thinking about converting to this: https://www.speedwaymotors.com/Tuff...ooth-Back-Ford-Alternator-100-Amp,278148.html. I have a 72 with tach and gauges and the junction block on the battery apron. Are you saying I should run the one wire from the new alternator to the junction block? BTW, my old alternator gauge isn't working. I may switch it to a volt meter, but until that happens, I assume that won't effect the charging system in any way. Correct? Thanks. Kevin.

 

[midlife]

I think that should work. The factory ammeters barely register with the engine off, key in ACC, headights on, doors open, cigarette lighter pushed in, brake lights on, and maybe the needle will deflect a half-needle's width. Think of the factory ammeter as an analog version of the alternator indicator lamp.

For the ammeter to work, one lead needs to register the alternator output, and the other lead the battery post. The use of the isolation post does that.

 

[kevken1959]

I think that should work. The factory ammeters barely register with the engine off, key in ACC, headights on, doors open, cigarette lighter pushed in, brake lights on, and maybe the needle will deflect a half-needle's width. Think of the factory ammeter as an analog version of the alternator indicator lamp.

For the ammeter to work, one lead needs to register the alternator output, and the other lead the battery post. The use of the isolation post does that.

Randy, what might be the advantages/disadvantages of the 100 amp one wire alternator? I'm hoping to eliminate possible electrical problems that might be caused by the external voltage regulator and hoping the extra juice may brighten the dash lights. The car I'm working on has some bad popping in the radio when running, but the radio sounds great with the engine off. I installed an FM booster because the signal was low. That helped the signal but not the popping. The radio noise suppressor is in place. How does the one wire alternator suppress radio noises if it doesn't have an external suppressor? Thanks. Kevin.

 

[midlife]

Depending upon the alternator, it may not produce until the engine reaches a certain RPM.
Going to a larger alternator DOES NOT provide more current or voltage; the voltage is regulated and current draw depends entirely upon your accessories and the car's needs. You CANNOT push current to solve your problems.

 

[kevken1959]

Oh. That sucks, lol. I found this brand new one wire alternator in my basement (been there for years and never knew I had it!). I've never installed one. Is that little wire what I'm supposed to hook up?

 

[midlife]

I have no idea; I've never wired one up (pun intended).

 

[kevken1959]

I have no idea; I've never wired one up (pun intended).

I found this video on youtube. . This one wire alternator is a little different than the ones I see today. Turns out the orange wire is for the alternator light. It's actually only a 60 amp alternator. Sure is pretty though! I still don't know about whether a radio noise suppressor is incorporated into these one wire alternators. It turns out this little gizmo is just a mini voltage regulator. I guess the newer versions just incorporate it into the alternator.