Charging problems on 1998 Mazda B2500

I've been through 5 alternators on this truck, and a new battery. Relays, and fuses are good...
All wire harness clips are tight and secure...
The alternator tests good. However I'm still not getting enough power to the vehicle. I have no idea where to go from here. Any ideas? Help would be much appreciated. We all know how expensive electrical rates are in an auto shop!

Asked by for the 1998 Mazda B2500
There's not much complication to this system. You could go through 5 alternators and not get a good one, depending on the quality of the part.

Ensure the alternator is putting out proper amperage and voltage.
Ensure the battery is of good quality and fully charged.
Ensure all connectors are clean and secure.

What is your symptom indicating that you have not enough power to the vehicle?
I bought a brand new battery and within a week it was totally dead