Big 3 upgrade harmful with extra battery?

I have been reading a little bit on the big-3 upgrade and it sounds like a useful tool... I was wondering if it would work even when I have a 200-amp relay between my normal car battery and my external Optima in the rear? Would the grounding be different in this case? Do I even need a big-3 upgrade with an extra battery? I am running a 2-amp system right now Punch Power 800.4 for the highs JBL 1200.1 for the subs (2 infinity perfect 12") I will be replacing the infinities with my new Alpine Type-x's soon (they're laying here on the ground lol) so I would like to know if a big-3 upgrade would be safe or even necessary thanks guys!!

safe yes. nessary always.JUST ONE MORE AMP!!!

hu,alpine cva 1005/dva 5205

sound processor,symmetry(first one).

sub amp,power 1000 the terminator.(1992).

subs,spl comp dual 1 ohms.

punch 150hd on a 10" ev.

alotofhighs

I got the big-3 information from sounddomain Do i follow the instructions as they are or do I have to mess around with my extra battery and relay also?

no the cardomain thread does it right for you any any other that need to do it. no needto alter the second battery.JUST ONE MORE AMP!!!

hu,alpine cva 1005/dva 5205

sound processor,symmetry(first one).

sub amp,power 1000 the terminator.(1992).

subs,spl comp dual 1 ohms.

punch 150hd on a 10" ev.

alotofhighs

allright -- thanks for the help I'll look into it... I'm scared to see what kind of mess I'm going to make with a '90 celica. It's a rats nest under that hood lol ;)

it's three simply wires. make good connection and follow the direction you have and you'll be fine. except the accessiblity of the alternator i believe thats acessed from the bottom. just take your time. you'll thank your self after you do these upgradesJUST ONE MORE AMP!!!

hu,alpine cva 1005/dva 5205

sound processor,symmetry(first one).

sub amp,power 1000 the terminator.(1992).

subs,spl comp dual 1 ohms.

punch 150hd on a 10" ev.

alotofhighs