1972 750 Norton Commando, Battery Keeps Dieing

Over the last 6 months I have been getting my 1974 Norton running. Everything runs great now, but the one issue I am having is my battery keeps dieing, when the battery is fully charged I have no prolems, but if I go on a long ride at the end of the ride the little Red Lite on the left of the headlight starts flickering when I am ideling, and bike starts running a little rougher, I will then try to use the blinker or horn and they do not work proper (The blinker sticks on, and the horn clicks, it does not honk when the battery is dead).

I tested the alternator, and got all the proper voltage readings out of it, it should be charging the battery, so then I thought well maybe it is the battery, so I went and had the battery tested and they said it was a good battery and was holding a charge (3 day test). Does anyone have any ideas of what I could do next to figure out why my Norton's battery keeps dieing? Any advice would be helpful.

Or the rectifier or Zener diode is faulty?

Or it could be a simple wiring connection problem?

How did you test the alternator exactly?

What voltage readings do/did you get at the battery with the engine running at high and low RPM with the lights off, and then with the lights on?

A faulty charge warning lamp assimilator has been known to cause charging problems, so you could disconnect it and then re-test: http://www.nortonownersclub.org/technic ... etail.html