I'm confused: "The battery is charging at 14.6 volts, the ammeter is discharging when lights are turned on, engine on or off-normal."
If ammeter is discharging when lights are on and engine is on, then alternator has an issue.
The first thing I would do is remove alternator and take it to Napa or Auto Zone and have it checked out.
Second, I would also take battery to town and have it checked out too.
Third is where the fun begins. Someplace you have either a bad connection, or the lights are drawing too many amps, short. I once had ground strap with a lose connection.
My alternators don't start charging until the RPM's are above 1200. When alternator wakes up I can slow engine down a little and it still works.
I would also put a voltmeter on battery. Ammeter pulses, the voltmeter should pulse a little.
Good luck. Let us know what you find.