more electrical problems.......

[S3 rich]

from cold:

battery light on before starting - normal.

start engine, approx 1800 rpm light goes off, alternator kicks in - normal.


from leaving upto 8 hrs (slightly warm):

ignition on, no battery light - not normal.

???????

have to then rev up to 3500rpm for alternator to kick in - not normal & loud.



can anyone shed some light? is it an obvious problem i cant see??

any help appreciated.

Richard.