I have tried one wire alternators with no luck. At idle, they just do not charge when dual fans, air conditioning, etc are on. I have given several away, and they have the same issues. So I am back to the factory three wire 63 Amp Alternator which charges like a champ even at idle, but just doesnt have to current capacity for the electrical load. I like the three wire because of the remote sensing and the alternator light, but mostly the remote sensing. I cannot for the life of me find a three wire alterrnator more than about 85 Amps, which is still not enough. Anyone have any suggestions. Most of the PowerMaster three wire alternators are not, they will drive the lamp but do not use the sense wire. This is on a 1977 C3 with a 383 Stroker, Dual HP fans, Vintage Air AC, fuel injection, etc etc, so the loading is quite high.

 

I have been using higher powered alternators for many years now and never had any real trouble. On the one wire alternators I have they have a plug that covers the voltage sense wire and the idiot light connections. One of them suggested that for earlier "turn on" that you need to run a voltage sense wire. The alternator I have now comes on at ~400 rpm so as soon as I get it to idle It is charging the battery. I had one years ago that waited until it saw about ~800 rpm before kicking on.

Call the people who made your alternator and see what they can do for you. Power Master alternators in the past have had a black rubber plug over the sense wire and idiot light plugs. I have had Power Master alternator's that came on using the sense wire

My C3 has it's 427 in it and running High compression the starter used to pull a ton of current. The current draw was reduced by changing the starter to a Gear Drive starter. Then I added a Holley Ignition Digital Retard which lets me pull the timing back 20* only while cranking and between both devices my engine pulls very little current while starting.
Our electric Fans are controlled by a DeRale PWM Electric cooling Fan controller which starts them up at 50% power and slowly ramps the speed up if the engine is continuing to get hot. You don't get that huge current draw starting 2 fans up at 100% power.

I also choose the biggest capacity battery I can fit and keep the terminals clean. When my C3 sits for a period of time I attach it to a 20 watt photovoltaic panel with quick connects, this keeps the battery fully topped off.

 

Look at Power Master 7294, described as either 3 or 1 wire, 100 amp.

 

Either go to a 140-amp CS-144 or you can wait until I finish documenting my DR44G alternator. It is easy to convert to either--- and I am going from a CS-144 to the DR44G ..... I am thinking that the DR44G might be easier and you will have better control over voltage....I'll update my post as I proceed.... I am going to the DR44G so I can bump up my voltage at idle to a steady 14+.... my CS-144 spikes down to like 12 vdc when the Mark-VIII radiator fan kicks on when I have everything running at idle (elc fan, a/c, efi, efi fuel pump, etc).....it recovers but I'd like it to stay at 14 vdc with everything running and idle at about 650-700.

Don't bother with 12si derivatives..... they're not good enough at idle for all your loads.... I have 94-amp 12SI that I replaced with the 140-amp CS-144.... the 94-amp 12SI works fine but it just CANNOT maintain terminal voltage at idle. If you lived close by I'd let you borrow it so you could see for yourself (I keep it for emergencies in case my CS-144 dies) ---

https://www.corvetteforum.com/forums...xperiment.html

 

I can't wait to see that!

I've been using a 150 A PowerMaster 12si 3-wire alternator. With everything running, my car draws about 45 Amps. No problem.

I'll replace it with a DG44 for consistency, though.

 

Right here Bro: https://www.corvetteforum.com/forums...-thread-4.html Post#77