so after having researched around a little i finally found a relay for more than 200 amps. the pac 500 off sonic electronics. here is my plan now having listened to all your opinions on batteries i came up with a new idea tell me if it sounds good.
i have my two 2150s on my dedicated system and a pc 1500 hooked up for my truck only running its own 300 amp alternator. my idea was to run the relay after the pc1500 to my buss bars allowing my amps to run off of all 3 of my batteries and 3 300 amp alternators. would this help eliminate my need for more batteries and by the way i am pretty sure i won't be playing my system at max for more than a minute or so.
thoughts, opinions, ideas. thinking of ways around more batteries lol not lazy more like space saving. thanks fellas