Batteries or Alternator?
I have a 2005 6.0PS. I noticed last weekend the truck would not start up as quick as usual. And the other morning, I went to head out to work and it was dead. Checked the voltage, 10+ volts. I put the charger on if for a while and got it running. I put the computer on it and found the car was putting out in the 11's at idle and would run up into the low 13's at higher RPMs. If I add lights and radios the voltage goes down. But it stays around 13.
Its been raining so basically I have just been leaving it on the charger over night and taking it to work and its been fine. Last night it was pouring, so I didnt put it on the charger and it was dead again this morning. I put a quick charge on it and got it started with a boost. Today I was looking at 9v and was lucky to get high 11s. If I turned off all lights, radios, A/C, etc I could get 12s.
I am leaning towards batteries, but would welcome your thoughts.
I am using AutoEnginuty to keep an eye on things, and yes I was watch the FICM as well and never dropped below 48 (phew!)