I'm tryin to get my car set for some high SPL and looking at multi battery how do i go about that. There has to be some charging issues would a regulator solve that problem?
you'd want to consider a higher output alternator to handle the stress of re-charging multiple batteries, but aside from that, you use a battery-isolator to separate the starter battery from the audio system batteries, then connect the batteries in parallel where you choose to mount them.