Alt Whine Issue

[2loud4uboyz]

Like someone already said. Ground the rear battery to frame.

[TRTC360]

^^^^^^ There's really no point in that, I'm running the best ground I can already. If it were a constant whine then sure id do the double grounds and recheck everything again but it goes away after being on for 1-3min.

[MECHMAN]

It could also be a failed diode connection in the alternator's rectifier that makes continuity once the alternator gets hot, which would explain why it goes away after a couple minutes,

If the alternator whine all of a sudden started out of nowhere with no changes to the wiring, there is a good chance it is the alternator, especially if it is a stock unit that is being hammered with a big system.