could one 270 amp alt. charge up my starting battery and 2 kinetik hc3800's or would i need 2 alt?

Could a plane fly without wings?

We don't know give us some information... WHAT 270 amp alternator? Who from? What does your electrical look like? Do you have 1/0, big 3, multiple runs of 1/0? What kind of system do you have? how many watts are you running?

We need accurate information to be able to give you an accurate answer.

We need accurate information to be able to give you an accurate answer.

yes i have the big 3 . im running 2 15"s juggernauts at .5 ohms each wired to 2 d-tower 3400's by soundstream, the ALt. is by mechman, i have lots of 0 gauge on the big 3 and running back to the batteries, i have the 2 soundstream amps and a t600 from rock ford for the mids and highs

We need accurate information to be able to give you an accurate answer.

sry for the confusion

We need accurate information to be able to give you an accurate answer.

im running about 7000 watts if that helps

What is the rated amperage output at idle?

What is the rated amperage output at idle?

160 amp idle at 800 rpm's

Do you actually idle at 800 rpm? lol. Go DC Power if you don't.

Also, you could get away with just one 270 alt but it kind of depends on how you listen to your system.

That alt will do just fine with that set up.