Need Alternator operation INFO ........ 2010 with approx 12k on it ........the alternator charges at 14.2 most of the time but after running for some time it will drop back to 13.7 and then down to 12.6 .....seems to do this after truck been running a while esp on highway ............does the battery have a temp sensor and when it gets hot reduces the charging rate ?? or do I really have a problem .......

 

It's normal and called regulated voltage control (RVC). It reduces the target voltage, 12.6-13.1, to help improve fuel economy. They have been using this since 2005

 

Thanks .........thought it might be something like that

 

Yeah looks different when you're driving down the road and look down and see it at 12 volts

 

There is a operation description in the owners manual on this topic.