Mex - I added a second Alternator SEPUP one time to my truck when we Lived in Texas back in the 60s... It had it own charge regulator and its two OUTPUTs went to a two pin HD connector mounted on the rear of the truck... This was supporting my Ham Radio emergency setups when we was on Weather Alerts every time the sky turned green...
My battery bank (Multiple 12V Batteries in parallel) for this was mounted in a utility trailer and it worked rather well when plugged into the two pin connections point on the truck using 4AWG cable pairs... Watching this with a multimeter it performed much like the OEM setup alternator - different DC voltage levels depending on the battery charge status I guess...
I added a second battery for it in the truck just to keep the regulator happy... I used this second battery only for running my two Ham Radio units in the truck... It always stayed charged up... None of this was connected to the truck 12V system...
Roy Ken
