Ford Repair: Explorer Charging system, tensioner pulley, charging system

Question
Coming home on I-80 in Wyoming yesterday my '07 Explorer would intermittently turn on the "check charging system" light on the dash. At first, it only came on when the vehicle shifted down climbing a grade. When I reached the top and the trans shifted back up the system went back to normal (I ran the onboard system diagnostics to check this). The belt looked normal, the tensioner pulley was visually okay. I was pulling a trailer back from UT (which I pulled to UT from CO without incident. I could find nothing physically wrong looking at everything but the condition did run the battery down. I charged it up to start the vehicle and that worked. Still today I encountered the same issue bringing my trailer to storage. Every time I demand a lower gear or additional power the charging system light comes on and then resets itself. Heard of this? I am going in for an alternator check tonight since I can't test that myself.

Answer
I need to know which engine and transmission is in this vehicle. is it 4.6 litre with a 6 speed transmission ? if so, there is a calibration update that can be perfored by your local ford dealer that ay address this issue. the service bulletin # is 07-2-8.
please let me know.. -b-