Have used 100 amp Powermaster one wire alts in two of my cars. Never had a problem with one, but the other was a nightmare. In that one the internal regulator went wacky and over charged the battery and which subsequently blew up. Also melted quite a few wires in the car, but luckily did not cause a fire. All of this happened in the middle of the boonies on a lonely interstate miles from anything. After a very long trailer ride everything was repaired and the alt was converted to a three wire. Have had no more problems since. Don't think I will ever intentionally use another 1 wire unit. Could have been a lot worse than it was, fortunately it wasn't.