I had a really nice conversation with one of the engineers at Powermaster. I learned a few things that may be worth repeating.
1) If you have 50 volts at the main terminal of your alternator, it means you have no load on the alternator. So, the problem ended up being an el cheapo fuse holder not making proper connection. All three of them are fine.
2) My local auto-electric repair shop guy told me that he doesn't like fuses in the main charging line. He cut me a 6 inch piece of Fusable Link line and said to put that in instead. On the other hand, the guy at Powermaster said to put a fuse inline because less damage would occur, like the difference between a fast blow and slow blow fuse.
3) Powermaster went on to say that a good way to resolve the 50 Amp meter using a 150 amp Alternator is to run a second charging wire direct from Alt to Battery. The second line acts as a bypass (shunt) and allows for an alternate current path. He was adamant that it makes more sense however to just put a voltmeter in your ride and just do away with the Ammeter completely.
4) Good news on more modern Alternator solutions is, the old Delco 3 wire Alts wouldn't charge until you hit about 1000 rpm (not sure but higher than idle) but the new 12SI ones they make have two advantages. One is, they start charging at about 500 rpm and the other is, they do not need any excitation wiring, they internally self excite. There is a plug over the two terminals and unless you want an alt warning light, this Alternator acts as a one wire solution. If you do want a warning light, it's a two wire solution. Pretty cool.
5) The last thing I learned was that it is perfectly fine to use an LED warning light. To do that, you need to put a 100 ohm, 1 watt resistor in series (before the LED or after) to limit the current the same way the incandescent bulb does. You read tons of things on the internet about this, all mostly conflicting with each other, but this was from Powermaster, so unless it doesn't work, I will feel on solid ground. More testing is needed.
