Curious low voltage issue

[Roustabout]

Hi

I have recently replaced my battery and had my alternator rebuilt by a reputable guy that has done good work for me in the past.

The last two mornings were pretty chilly. Yesterday morning I fired up the truck and noticed that the battery light stayed illuminated. The voltage was showing 11.5 on the scangauge. I shut if off and immediately fired it back up and the everything appeared fine - no battery light and scangauge showing 14v.

This morning I verified the battery voltage before firing up the truck with a multimeter - 12.5v - no problem. I then fired it up and bingo - battery light and scangauge showing 11.5v. I read the voltage at the alternator and battery with a multimeter while idling and got 11.5v. Switched the truck off and re-started and everything read 14v again.

Any ideas? Does the voltage regulator in the alternator have any moving parts that could stick in the cold? The serpentine belt is relatively new and I didn't notice any slippage.

Thanks

 

[oakley]

Next time it does it give the engine a little rev... i have seen regulators not kick in until a certain rpm or voltage was seen,,,mite be a glitchy reg or sticky brush