I bought a Powermaster 12si 100 amp alternator (part#27294) and the Lectric Limited three-wire conversion harness.

Works like a champ!

Next step will be relays for the headlights.

 

 

A sales pitch for what? They don't sell alternators.

Anyway, anyone who doesn't want to know that their alternator has quit working before the engine dies is more than welcome to install a one-wire unit.

 

the factories try and economize to the maxium possible, so why would factory engineers and cost accountants want to use a more complex three wire system versus the good ol tractor alternator set up? What a three wire set up does is read the voltage at the bus not the battery. its the bus you want at the correct voltage not the battery.

 

I'm Batman is absolutely correct about the location of the alternators sense wire.

A one wire alternator senses battery voltage at the output terminal of the alternator. It is at that location that the alternator raises the output voltage to 13.6 to 14 volts.

A stock corvette alternators output is connected to the horn relay with a #10 wire and then another #10 wire to the battery ( starter ). Power distribution for the car is from the horn relay. That means when you have your lights, wipers, etc. turned on, there is a voltage drop across the #10 wire from the horn relay to the battery ( starter ).

You can see that the 13.6 volts at the output of a one wire alternator is decreased by any voltage drop the accessories cause across the #10 wire from the horn relay to the battery. This limits the maximum amount of current the one wire alternator will supply.

If you simply hook up a one wire alternator output the existing alternator red wire you will never see the full capacity of the larger alternator.

The stock system has a sense wire connected directly to the battery ( starter ) that tells the generator to raise the voltage to 14 to 14.8 volts making up for the voltage drop of the stock wiring.

Charging systems always sense battery voltage at the battery!

Now, if you install a one wire alternator with a new, properly sized wire from its output to the battery, you will realize the full capacity of the larger alternator.
CUL Jim

 

What???

 

One more question before I head up to the north woods of Wisconsin for a few day: Of all you guys that get on this forum and tell the world what a POS the one-wire alternator is, how many of you have owned one?

I say they work fine, and I speak from 12+ years of experience.

 

no offense intended, but i guess after all these years of occasionally owning a POS (or is that spelled FORD); i just know a POS when i see/smell one, don't have to own one anymore...

but to answer your question; no, i've never owned one. BUT everything i've ever read says that they are for very specialized uses and not daily drivers...

enjoy your trip...
Bill

 

I had a powermaster 140 amp 1-wire, it lasted about 2500 miles & expired.

 

Warning light.

 

Let me guess...it was built on the 10SI housing that was never designed to handle that kind of power. There were a ton of failures reported in the C3 forums last year with those units.

 

FYI: John Deere has been using the AC Delco (three wire) alternator since 1972.

Before that, it was a generator on the 24 volt system.

 

Deere has always kind of done things their own way...