Low charge when hot.

No, I don't have a load tester. Best I can do is get the battery or alternator checked at an auto parts store. At idle I know the alternator would fail when the car is hot but pass when it's cool. I guess I could get another alternator since it's under warranty but I don't know if that would fix it.

When its hot, could check for the voltage at the field terminal with blue wire.
Could also full field the alternator to see if that brings the voltage up.