alternator help!!

[fantombiker]

I have a problem that's driving me mad. The alternator is not charging the battery. I have replaced the alternator, the battery and the fat wire that goes to the starter. I get a Voltage from the Alternator when the engine is going, but the voltage across the battery drops to about 5v when I rev the engine. The wiring goes through an FIA master switch. Any idea?

Car is a vhpd powered s3 k series.

[radical78]

does the charge light work . if this circuit is broken the alternator wont work