did you also upgrade the gauge to your amp? If i go 0 gauge big 3 i assume i have to go all the way to the amp.

 

yellow tops, unless they've changed, are actually not really a great thing to use as your primary battery. They're deep cycle batteries, meaning they're meant to be charged, then drained, then charged then drained, and so on. You see yellow tops used a lot in MA because they're used in battery banks, where there will be 20-60 batteries daisy-chained and being used ONCE for a big, fat, SPL "burp".

And, no, you will not have to run 0awg to the amp. 4awg is plenty for the amp you're running, as long as you didn't make some obscenely long turns around things to get to the amp. Check the fuse on the amp itself, and report back to us what amperage it is. Should be 2x30a by what I found. This means the amp is probably drawing about 50a of current. Using a calculator (like this one, the first one I found) I show that at a 3% loss, you should be fine with 2awg, which isn't too common, and I don't even know if the amp would accept a 2awg feed without being terminated with a solder-on/crimp-on "tip".

What you COULD do, is run 0awg back to the trunk, ending at a distribution block, where it would turn into a 4awg lead to your amp. This would allow you the flexibility of adding another high-current draw amp, as well, not to mention a low-draw amp.

Cliff notes: 4awg is fine back to the amp.