WH Statesman voltage issues

[moocow]

Hey guys,

I have a 2001 WH LS1 Statesman.
My alternator recently died and I just replaced it today.
I started it and checked the voltage across the battery terminals and it was just above 14v, so where it should be.
I drove around town and everything seemed good.
Got out on the open road and put my foot down and my headlights and dash lights all got really bright and then my dash cut out and warning lights came on.
Pulled over, put the car in police mode or whatever it's actually called and tried again. The voltage at one point under high rpm read over 17v! And now on idle I only get 11.7v across the battery terminals. This voltage is confirmed on the digital display in the dash.
What the hell is happening and how do I fix it?
Any help greatly appreciated!

 

[Immortality]

Check the main charge lead from the alternator to the battery, if this is loose or damaged it can cause trouble, also check the voltage sensing wire is in good working order.

 

[moocow]

Had a look at the charge lead and looks like it's been seriously hot. It's brown and crispy starting from about an inch before the terminal at the alternator end.
Looks like I'll be replacing that lol
Are there any fusible links on the charge lead?

 

[accentstencil]

Did you replace the alternator with a new or secondhand one, because it sounds like the voltage regulator is stuffed.

 

[Immortality]

Had a look at the charge lead and looks like it's been seriously hot. It's brown and crispy starting from about an inch before the terminal at the alternator end.
Looks like I'll be replacing that lol
Are there any fusible links on the charge lead?

No, the charge lead is just a standard cable. Might pay to go one size larger if you intend to make your own one up.

The battery voltage sensing wire does have a fusible link, might pay to check that out if the alternator isn't putting out any charge after fixing the main cable.

 

[moocow]

Pretty sure it's a reco one cause I got it through all crash. Looks quality though.

Ok well I plan on getting a new lead today. I don't know what size the standard lead is though.

Any idea on the location of the link on that wire?

 

[Immortality]

The link is the first bit where it bolts to the battery terminal, it's an old style fusible link where it is literally the bit of wire that burns out.

 

[moocow]

Oh true, I've seen them before. Didn't think to look for one on this car though haha
I'm amazed I didn't blow anything else with the voltage as high as it was.

 

[moocow]

So I've replaced the alternator charge lead and still no change.
I tested the fusible link with a multimeter and it's not broken. I even bypassed it with no luck.
Could it be that the voltage regulator in the new/reco alternator is faulty?

 

[moocow]

Just went for a drive and the voltage stayed between 11v and 11.5v

Battery reads 12v when the engine isn't running but drops to 11.5ish when it is.
Safe to say I'm confused.