Alternator not fully charging?

[M A C]

Battery again flat and wouldn't take a charge on my 996. Checked warranty on battery replacement at local motosave and found just less than 3 years old and still under warranty.
Took the car into day and they tested battery and said it was faulty,( which they replaced foc)they also tested the alternator and said it was putting in between 1 amp to quarter less than it should be putting back into the battery'.
Have had alternator fail completely years ago but never had one not fully charging,
Are these repairable or just new replacement and any idea on cost?

[NBTBRV8]

Many years ago my 996 stopped charging. I replaced the alternator with a Bosch one, which is the same one that was fitted just without the Porsche part number on it.

I believe the regulators fail, but as they are ageing now just replace the whole things as the bearings will be well worn anyway.

[LeighB]

I had charging issues on mine last year. After first trying a new battery and then replacing the alternator it wasn't sorted. Then my starter motor failed and replaced that.

Charging issues cured lol.