Vehicle - 1995 GMC S1500 with the 4.3L V6. 106K miles. Original damn near everything, except spark plugs.
New Napa battery installed July of 2018.
The battery warning light came on. Voltage meter dropped down to about 10V. I was on the way to pick something up, but turned right around and got it back to the driveway.
In the driveway, the truck started 4 more times, each time the battery was a bit lower.
The battery will take a charge from a trickle charger and start the truck a bunch of times. When the battery was dead it would jump start successfully too from the charger. I cleaned all the terminals and battery cables - they were very good already though since I did all that last July.
I think the alternator is dying and should be replaced. While I am at it, it is really due for a timing chain and water pump. That all sound about right?