I had check charging system warning light intermittently coming on, voltage would drop down to 12v and at times down in the 11v range and then would reset. This went on for about 1 month and seemed to slowly get more frequent and would stay on longer before it would magically reset and begin to charge normal. Ended up having the alternator replaced this weekend and it fixed the issue. This is a 2013 Ford Edge SEL with the 3.5L motor with 228,000 miles.
BTW. Make sure to replace serpentine belt, power steering belt, and tensioner along with the alternator while you're at it.
I purchased a new alternator for ~$240, tensioner ~$70, and belts ~$30.
The mechanic took the radiator out to get the alternator out so I did have to buy a gallon of antifreeze also.
