I wanted to install a port for plugging my system into wall power, instead of using the batteries, since the charger doesn't recharge them faster than they can discharge, and I was wondering if I could just wire the port right in without a switch. Will the wall power override the batteries if it has a higher amperage, or will I need a switch for shutting off the batteries from the circuit?

You'll need a switch.

That's what I figured, thanks. If both were connected, would it just use the batteries' charge?

No something would blow up.

Really? Won't the charge protection circuit prevent that?

No.