Got a silvertop GQ td42 with vac pump on alt in a GU4

my auto8 alternator doesn't give any voltage until 1300 rpm
my original Hitachi one died and it used to charge at idle once I excited it
and revved it a little bit to wake it up but it too struggled with lights on,
demister and ac on

I'm looking at replacement alternators to buy and alot of the reviews
are saying the same thing ( crap voltage at idle )

What is with all the crappy alternators that don't charge at idle
or can't hold 14v with the AC fans and lights on?


Can anyone recommend a alternator brand that will charge at idle
with the AC fans and lights on?