I used a sunpro instruments CP8215 volt gage, and used just its guts. Reinstalled my ammeter face after modifying it to fit. This was a mod shown elsewhere on fabo i just copied what was done.
I drilled out the old ammeter gage mounting holes in the gage housing and installed plastic grommets that came with the sunpro gage to insulate both studs. The ground stud i shimmed with a nut and washer and made sure it grounded to the gage housing. The positive stud you can see in the pic has a red plastic insulator
On the back side of the gage housing i made a 14g jumper wire from the volt gage positive stud to the 12V input for the initial gage feed from the wiring harness. This way it has power, and case ground. The pic shows a black ground wire i have since eliminated since the gage is now case ground. Only the red lead remains.
The alternator is a mini nippondenso 50A. Which required an 8 ga wire as output. This required removal of the original ammeter and wiring as 8 gage wasnt going to fit the bulkhead connector, and i wasnt going to put a major hot lead thru my firewall in a grommet.
I modded the ammeter circuit, and sent dual leads from the bulkhead that were for the ammeter and dash feed both straight to the battery with a fusable link at the battery. Actually tied them in at the starter relay lug.
Then my alternator 8 ga lead went straight to the battery with its own fusable link.
I could take a crapload of pix and post em up here, but with my upload rate, and resizing them some of the detail will be lost making it a bit hard to figure out.
Here is an alternator mounting pic though. The alt cost ne $87 new, is a 50A and weighs about 5 Lbs, and the 1/8" thick custom made brackets are 7475 T6 aluminum plate and weigh about 12 oz. Spacer was trimmed out of steel blackpipe from home depot to remove the threaded ends, then trued up on a lathe at work. The spacer for the adjustor strap to the lower alternator mount is a machine turned down aluminum spacer made from a SAAB 340 B aircraft overhead bin spacer, though anything could be turned down to be used. The adjuster bolt is 13mm which i left insteadbof tapping for SAE thread since a 1/2" wrench will fit a 13mm.
Heres sideways and upside down pix again lol.