Amp Meter ByPass

Search my post "Modernized Engine Wiring" or such. I use a diode-pair as a "progressive ammeter bypass", so I keep the ammeter functional but don't over-range it. I also installed a 95-99 Jeep fuse/relay box. But those take 60 A max fuses I recall. I bought a separate ~180 A fuse at Autozone for the BATT+ connection (after starter current). I bolted that to the Battery Brain I use.

Re current output needed, I just measured my 1996 Voyager since I suspected its alternator was not outputting OK (still original at 205K mi). I have a clamp-on DC ammeter that I measured right at the alternator output. I measured ~40 A with AC clutch on, cabin blower high, headlights high-beam, and radio on, which is probably a typical load for an EFI engine (though a 4 cyl). When the 2 radiator fans turned on, it jumped to 60 A. I probably have the base 90 A alternator, so still ample head-room (and works fine). There is a 120 A alternator option, but no need. I don't think the radio draws much unless you are "all about that bass" and put in a ground-thumper (also need stiffer T-bar on R side if bass babe rides shotgun). Don't calculate based on fan nameplate since probably the starting surge current. Steady running is probably ~10A per fan, but more if the Ford 2-spd fan which hot rodders use. Your engine-driven fan should do 90% of the job, w/ electric just to help the AC condenser. BTW, my 1996 alternator is the same "isolated field" type alternator as the squareback in 1970's Darts, though a Nippondenso.