Ok I misunderstood. Now that I have re-read....Do you have "normal" ammeter readings in the day? How many hours per week/month?
Repeating what has been said......Other than the starter at 300+ A, the headlights draw the most. With sealed beams about 100A on hi beam. The battery will get recharged pretty quickly after start. The old faithful test is during the day, drive it and observe ammeter. Then switch on headlights and observe. Should be "normal" (settling needle at middle or slight charge), then when headlights go on, needle should tick to discharge and creep back to middle or slight charge within a fairly short time.
That test and the other two will expose the issue more clearly.
