Fuse to battery in the back?

from the front one?

Not sure if it's necessary but almost everyone does. One fuse right after the front batt and one right before the back one. So 2

i do as its to protect the battery(s) in the back

edit: and if someone can prove this to be wrong please do so would save me some fuse holders in the future

i dont fuse it 2 times between the font and back. One fuse between the 2 batts then one after the batt before the amp

Well I have a 300 amp fuse on the line running to the back just to be safe. The only reason I was asking is because I would gain 0.3 volts at idle if I didn't have a fuse on the line. Then for the run running from the rear battery to the 1500 I just used a 200 amp.