Ammeter, shows at best charge/discharge. A Volt meter will tell you more, if needed. What did you add to your truck that needs 80 amps? Modern car/truck thinking leans to electric powered stuff like windows, steering, and Tech goodies(includes about 100 sensors, computer, GPS, entertainment and who knows what). Oh don't forget AC and big heater motors, and electric doors to move air around the inside. We don't use much of that stuff, do we? The question, is a good one. Ammeter, or Volt meter. I like both, but then my truck has a radio and a heater. I do have an Alternator, it came with the truck. External regulator and all. It works but, darn, it is ugly. Just looks wrong next to the engine. But that is me. An under dash volt meter makes sense, even an under hood one would make sense. But I can pop the top off the battery cover and put one on the battery if I need. With good wires. Proper sized wire. Even a big amp alternator will be fine. Add a shunt if you need peace of mind. The line between a "Daily driver", Restoration, Hot Rod/Custom, are fuzzy on a good day. Does a daily driver need to be 12 Volt? No. Is a 12 Volt a Restoration? No. Is a 235 a Hot Rod? No. Is my truck fun? Yes. Enjoy yours.
