Alternator works fine during the day, nice 13-14 volts & charging.
At night, head lights drop it to 13 volts, BUT if I load it up any more (brake lights or wipers on), the volt meter drops down to 10-11 volts (discharge), belt makes a very light short screech. When the load is removed the voltage still stays on 10-11 volts and won't start to charge again (alternator cuts out for some reason). Stop car for about 20 min and everything goes back to normal until overloaded again.
Any ideas please?
393 Tremec TKO 9"