I recently installed an FD alt into my s4 gxl. I double, tripple and quadruple check my wiring and they looks good and correct.
But I noticed that my main fuse (black) is only 80A. Should I "up" the main fuse to 100A or more??

 

No. There is no reason to change the main fuse out.

 

so, with all cables remove...and main fuse remove.
on this first pic i got an open circuit to ground

 

and on this pic i got a short to ground..

 

is this suppose to be?? the first pic is short to (+) and second pic short to ground, so isnt this mean shorting batt to ground??