run a + line from front batt to + second batt with a fuse 8 inch away from batt 1 and 2 (so 2 fuses) ,
then groound wire from amp to 2 batt at the - post
ground that same - post to body of the car somewere in the truunk
wire negitive terminal from 1st batt to body as well
run power wire from 2 batt to amp with fuse inbetween