Alternator charging system seems to jump up and down, I suspect it is the voltage regulator which is inside of the alternator, I took the car to the dealer twice and they said the charging system is just fine. That was last month, Now I am getting stranded from the battery being drained from not having a sufficient charge. I have a voltage reader that plugs into the cigarette lighter, when I see it drops down to 12.8, 12.4 , 11.8 I have to pull over and restart the car so it can start charging again. I recently noticed when I turn the steering wheel that triggers it some times.