Could my starting issue be coming from my alternator

Two nights ago I changed my fuel pressure regulator on my 1999 Suburban K2500, 7.4L. It was suggested that I pull off the upper intake to perform that task but I didn't need to and just pulled the coil and the distributor cap and wires after pulling all connection that were in the area. This made it pretty accessable. Anyway after I put everything back in place I tried to start the truck and it acted like the battery was very low and just the starter solenoid clicked. I proceeded to jump the battery but the charger showed that it didn't want to take the charge. I quickly went back through the wiring and found nothing pinched or out of place. I quit for the evening and checked it again last night and found one of the large 30 amp fuse blown ( Auxilary A - in the engine compartment). I replaced it but nothing changed. I thought one of the battery cells shorted internally and changed my battery. That battery was holding 16 volts. But then also there wasn't a load on it and didn't have time to load test it. I puut the new battery in the truck and it tried to start but it was late and I started again tonight and once again the battery was at a very low state and the motor turned over very slowly.
I only worked on the fuel system not the wiring. I checked everything in the wiring dept again but nothing is pinched. Something had to have coincidentally happened to cause this. I personally think this is a stupid question but could the alternator have gone bad creating this problem?