I recently installed a Powermaster 1 wire alternator. I like it a lot so far. I don't have to rev the engine to get it to start charging. It puts out 14.4 volts even at the lower RPMs. According to their website, they offer some one wire alternators that will work with a charge light with the addition of a small harness. Time will tell if it is truly an excellent product.



I don't remember which brand I had but I had to rev the engine to about 1200rpm to start charging and the voltage would start to drop off at about 700rpm. The pulleys look to be the same diameter.


Lawrenceville, GA

I put a one wire on a '55 bird, and found I only had about 12.4 volts at the battery.  The one wires look at the voltage output at the alternator (there's a shorting plug in most of them).  I ran the other two wires, taking the "sensing wire" back to the battery, and voila! 13.7 volts at the battery.  I've had a couple powermasters fail, but possibly due to high underhood temperatures.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Because the "one wire" is using the battery feed as the sensing voltage - the bigger the battery line the better (less voltage drop). Use a sensitive (digital) meter and check the resistance from the alternator connection to the battery (+) post. Mine had too much. 

So - on the green bird I used a piece of #6 welding cable with soldered copper lugs. Now full charging voltage is available.

Make sure there is no resistance between the alternator case and the other "grounds"  - the block, the frame, the battery (-) post. The highest voltage on the vehicle exists between the alternator rotor poles and the case of the alternator - and you would like to be using that voltage. So make all of the grounds as "low" as the case. 

 
 Steve Metzger       Tucson, Arizona