Ammeters have been run with alternators for millions of miles. I have run my Suburban over 20,000 miles that way and no telling how many put on it before I bought it.

Also, of course people who sell voltmeters will tell you you need one. Do you expect them to say you don't need this but we'll sell you one anyway?

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.