VT Calais Not Charging

[Captain Steve]

Hi everyone; I have a 2000 VT Calais V6 Supercharged. In pretty good nick, done only 190,000 kays. The thing is that the alternator karked it and was puttin' out 15.5 volts. I bought a new one, a Bosch, but I'm only getting a reading of 11.6 volts at the battery terminals while the engine is running. I passed the alternator back to the parts store to have it checked. They returned it to me saying it was o.k. There's no problem with the BCM or ECC modules. I'da thought that if the alternator is fine it would show well over 12 volts at the terminals? I've checked two earths. Are there anymore, and would a bad earth cause the undervolt problem? I'm wondrin" if I should get the alternator checked again.................

 

[Not_An_Abba_Fan]

Check the main feed wire off the alternator, they have a habit of burning and then having high resistance. See if the insulation near the terminal has burnt. If it has, cut it back and fit a new terminal.

 

[krusing]

The nominal Output Voltage would/should be, idling is approx 14.2 > 14.6 volts,
Turn the Head Lights on and voltage probably drop to approx 14.2,
and the alternator will compensate for the current being drawn, and should go back up to approx 14.6.
Could the Battery have a dead Cell ?,
Depending upon the age of the Battery, and since you have installed a New Alternator,
I would be also replace the battery,
Then you know Both items are in good order, and shouldnt have a issue with them for a while.
You would hate to cook a New Alternator.