I've kind of done a 180 on my thinking about 1 wire alternators. I had been a defender of them, saying all the BS about how they can't work is just that, BS. I had one on my Jeep for years, and also on several boats, and they worked well. However, I now have to admit the Powermaster one on my current T is a slight disappointment.

Oh, it works and the battery stays charged (it is a 100 amp model) but at idle the voltmeter gets down a little until I touch the gas and then it will pop up a little more. Highway speeds are fine, 14 volts or thereabouts. I can actually watch my headlights dim at traffic lights, and brighten when I increase the rpms. That surprised me, as the Jeep never did that. However, the one on the Jeep was a marine alternator that I adapted, so maybe this problem is just a Powermaster issue?

But otherwise, it is fine.

Don

You may have a alternator speed issue at idle. Like so many of the "underdrive kits" they trade off keeping the alternator output at a higher level at a lower rpm for a couple of top end horse power. Street Rodder magazine did an awesome article a couple years ago on this very topic. I don't remember exactly when but I'm sure some others may. If you can locate a handheld Tach and measure the pulley speed, Powermaster can tell you if it's turning fast enough at idle. They also provide a tag that shows output for a given rpm. Did you keep that tag? It may prove helpful!